Catch all exceptions whilst trying to check if PyPI module available. (#1848)
Catch all exceptions whilst trying to check if PyPI module available. (#1848)

* Catch all exceptions whilst trying to check if PyPI module available.

If this operation fails, the whole CLI shouldn’t through another exception.
We should catch it.

* Add comment explaining AttributeError

QingChenmsft/azure-cli,QingChenmsft/azure-cli,yugangw-msft/azure-cli,QingChenmsft/azure-cli,samedder/azure-cli,QingChenmsft/azure-cli,samedder/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,samedder/azure-cli,yugangw-msft/azure-cli,samedder/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli