[VXLAN]Fixing traceback in show remotemac when mac moves during command execution

[dgsudharsan]

What I did

During the execution of show vxlan remotemac command, if a mac moves after the key is fetched but not the table fields, there will be the below traceback

show vxlan remotemac 2.2.2.2 
Traceback (most recent call last):
  File "/usr/local/bin/show", line 8, in <module>
    sys.exit(cli())
  File "/usr/local/lib/python3.9/dist-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python3.9/dist-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python3.9/dist-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python3.9/dist-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python3.9/dist-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python3.9/dist-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python3.9/dist-packages/show/vxlan.py", line 310, in remotemac
    rmtip = vxlan_table['remote_vtep']
KeyError: 'remote_vtep'

This is because the entry would have got removed before the CLI fetches the table.

How I did it

Used get API to fetch table rather than indexing directly which resulted in traceback. Additionally fixed Python 3.8 SyntaxWarning.

show vxlan remotemac all
/usr/local/lib/python3.9/dist-packages/show/vxlan.py:101: SyntaxWarning: "is not" with a literal. Did you mean "!="?
if vtep_sip is not '0.0.0.0':
/usr/local/lib/python3.9/dist-packages/show/vxlan.py:108: SyntaxWarning: "is not" with a literal. Did you mean "!="?
if vtep_sip is not '0.0.0.0':

How to verify it

Perform mac move during show command execution and verify there is no traceback.

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)

[lgtm-com]

This pull request introduces 1 alert when merging 01796d2 into c497c84 - view on LGTM.com

new alerts:

• 1 for Testing equality to None

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[lgtm-com]

This pull request introduces 1 alert when merging 5be7c2c into c497c84 - view on LGTM.com

new alerts:

• 1 for Testing equality to None

---

Heads-up: LGTM.com's PR analysis will be disabled on the 5th of December, and LGTM.com will be shut down ⏻ completely on the 16th of December 2022. Please enable GitHub code scanning, which uses the same CodeQL engine ⚙️ that powers LGTM.com. For more information, please check out our post on the GitHub blog.