Buckets with retention policy defined

gcsfuse doesn't work correctly with a bucket that has a retention policy defined on it.
```
$ mkdir mnt_bucket
$ gcsfuse --dir-mode 755 --file-mode 777 --implicit-dirs --debug_fuse gcs_bucket_with_retention ./mnt_bucket
Using mount point: /home/oracle/mnt_bucket
Opening GCS connection...
Opening bucket...
Mounting file system...
File system has been successfully mounted.
$ ls -l ./mnt_bucket/
total 3430
-rwxrwxrwx. 1 oracle dba 0 Oct 21 22:07 test.txt
$ echo Hello > ./mnt_bucket/test1.txt
$ ls -l ./mnt_bucket/
total 3431
-rwxrwxrwx. 1 oracle dba 0 Oct 21 22:07 test.txt
-rwxrwxrwx. 1 oracle dba 6 Oct 22 15:11 test1.txt
$ cat mnt_bucket/test1.txt
Hello
cat: mnt_bucket/test1.txt: Input/output error
```