Read entry log metadata by log file name does not work.

**BUG REPORT**

***Describe the bug***

Use `bin/bookkeeper shell readlogmetadata 2.log` does not works but `bin/bookkeeper shell readlogmetadata 2` is works.

***To Reproduce***

Steps to reproduce the behavior:
1. Use bin/bookkeeper shell listfilesondisc -entrylog to get all entry logs
2. Read log metadata of one entry log by the entry log file name
3. See error

```
Exception in thread "main" com.google.common.util.concurrent.UncheckedExecutionException: No file for log 0
at org.apache.bookkeeper.tools.cli.commands.bookie.ReadLogMetadataCommand.apply(ReadLogMetadataCommand.java:106)
at org.apache.bookkeeper.bookie.BookieShell$ReadLogMetadataCmd.runCmd(BookieShell.java:1048)
at org.apache.bookkeeper.bookie.BookieShell$MyCommand.runCmd(BookieShell.java:236)
at org.apache.bookkeeper.bookie.BookieShell.run(BookieShell.java:2235)
at org.apache.bookkeeper.bookie.BookieShell.main(BookieShell.java:2326)
Caused by: java.io.FileNotFoundException: No file for log 0
at org.apache.bookkeeper.bookie.EntryLogger.findFile(EntryLogger.java:960)
at org.apache.bookkeeper.bookie.EntryLogger.getChannelForLogId(EntryLogger.java:895)
at org.apache.bookkeeper.bookie.EntryLogger.scanEntryLog(EntryLogger.java:976)
at org.apache.bookkeeper.bookie.EntryLogger.extractEntryLogMetadataByScanning(EntryLogger.java:1137)
at org.apache.bookkeeper.bookie.EntryLogger.getEntryLogMetadata(EntryLogger.java:1046)
at org.apache.bookkeeper.tools.cli.commands.bookie.ReadLogMetadataCommand.printEntryLogMetadata(ReadLogMetadataCommand.java:132)
at org.apache.bookkeeper.tools.cli.commands.bookie.ReadLogMetadataCommand.readLogMetadata(ReadLogMetadataCommand.java:125)
at org.apache.bookkeeper.tools.cli.commands.bookie.ReadLogMetadataCommand.apply(ReadLogMetadataCommand.java:104)
... 4 more
```

***Expected behavior***

The readlogmetadata command should work with the log file name.

Start in ReadLogMetadataCommand.java, where the readlogmetadata argument is processed, then follow the call through BookieShell.java to EntryLogger.java. Reproduce the command with both 2.log and 2, and consider the issue done when metadata can be read by the full entry-log filename as well as the numeric log ID.

Written by the indexing model from the issue text.