script is downloaded but not run on Centos 7.4

The machine OS is automatically upgraded from 7.4 after the custom script extension start to install to Linux (centos 7.6.1810)

here is the log
File downloaded permissions:
```
-r-x------. 1 root root 270 Jul 1 10:24 setup.sh
-rw-------. 1 root root 95249 Jul 1 10:30 stdout
-rw-------. 1 root root 111 Jul 1 10:30 stderr

```

```
stderr content:
Error: Nothing to do
Non-fatal POSTUN scriptlet failure in rpm package WALinuxAgent-2.2.18-1.el7.centos.noarch
```
```
/var/lib/waagent/Microsoft.Azure.Extensions.CustomScript-2.0.7/bin/custom-script-extension install
time=2019-07-01T10:24:01Z version=v2.0.7/git@1f9c51c-clean operation=install seq=0 event=start
time=2019-07-01T10:24:01Z version=v2.0.7/git@1f9c51c-clean operation=install seq=0 status="not reported for operation (by design)"
time=2019-07-01T10:24:01Z version=v2.0.7/git@1f9c51c-clean operation=install seq=0 event="migrate to mrseq" error="Can't find out seqnum from /var/lib/waagent/Microsoft.Azure.Extensions.CustomScript-2.0.7/status, not enough files."
time=2019-07-01T10:24:01Z version=v2.0.7/git@1f9c51c-clean operation=install seq=0 event="created data dir" path=/var/lib/waagent/custom-script
time=2019-07-01T10:24:01Z version=v2.0.7/git@1f9c51c-clean operation=install seq=0 event=installed
time=2019-07-01T10:24:01Z version=v2.0.7/git@1f9c51c-clean operation=install seq=0 status="not reported for operation (by design)"
time=2019-07-01T10:24:01Z version=v2.0.7/git@1f9c51c-clean operation=install seq=0 event=end
Writing a placeholder status file indicating progress before forking: /var/lib/waagent/Microsoft.Azure.Extensions.CustomScript-2.0.7/status/0.status
+ nohup /var/lib/waagent/Microsoft.Azure.Extensions.CustomScript-2.0.7/bin/custom-script-extension enable
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event=start
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event=pre-check
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="comparing seqnum" path=mrseq
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="seqnum saved" path=mrseq
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="reading configuration"
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="read configuration"
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="validating json schema"
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="json schema valid"
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="parsing configuration json"
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="parsed configuration json"
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="validating configuration logically"
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="validated configuration"
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="creating output directory" path=/var/lib/waagent/custom-script/download/0
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="created output directory"
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 files=1
time=2019-07-01T10:24:03Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 file=0 event="download start"
time=2019-07-01T10:24:04Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 file=0 event="download complete" output=/var/lib/waagent/custom-script/download/0
time=2019-07-01T10:24:04Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="executing command" output=/var/lib/waagent/custom-script/download/0
time=2019-07-01T10:24:04Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="executing public commandToExecute" output=/var/lib/waagent/custom-script/download/0
Not writing a placeholder status file, already exists: /var/lib/waagent/Microsoft.Azure.Extensions.CustomScript-2.0.7/status/0.status
+ nohup /var/lib/waagent/Microsoft.Azure.Extensions.CustomScript-2.0.7/bin/custom-script-extension enable
time=2019-07-01T10:30:27Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event=start
time=2019-07-01T10:30:27Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event=pre-check
time=2019-07-01T10:30:27Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event="comparing seqnum" path=mrseq
time=2019-07-01T10:30:27Z version=v2.0.7/git@1f9c51c-clean operation=enable seq=0 event=exit message="this script configuration is already processed, will not run again
```

Inizia dal punto di ingresso di enable registrato di custom-script-extension e dal setup.sh scaricato su CentOS 7.4/7.6, quindi traccia il modo in cui i file di stato/sequenza fanno sì che il secondo tentativo di enable segnali che la configurazione è già stata elaborata. Done deve essere dimostrato con una riproduzione in cui lo script scaricato viene eseguito come previsto e l’estensione segnala il risultato corretto.

Scritto dal modello di indicizzazione a partire dal testo della issue.