Remove trailing dash from tunnelstat cache directory name

[LGH-12]

What I did

Remove trailing dash from tunnelstat cache directory name

admin@sonic:~$ tunnelstat -c
Cleared counters
admin@sonic:~$ ls /tmp/cache/tunnelstat
1000-

# Other cache directory name
admin@sonic:~$ ls /tmp/cache/intfstat/
1000
admin@sonic:~$ ls /tmp/cache/portstat/
1000

How I did it

Tag should be None，if no tag parameter is provided,

How to verify it

on a DUT:

admin@sonic:~$ tunnelstat -c
Cleared counters
admin@sonic:~$ ls /tmp/cache/tunnelstat/
1000

Previous command output (if the output of a command-line utility has changed)

New command output (if the output of a command-line utility has changed)

[mssonicbld]

/azp run

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[mssonicbld]

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[mssonicbld]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).