[ClusterLabs Developers] Resource agent change review for azure-events

[Rich Paredes]

Proposed commit is here: https://github.com/rfparedes/resource-agents/commit/4f6f5e9634092a3db2e61258f24165c6fecfadc5

Specifically these changes are meant to fix "URLError is not defined" being generated when communication fails to IMDB for whatever reason, in this case due to the VM's underlying host having gone into unhealthy state:
2020-12-04T08:38:49.108342-05:00 HOST /azure-events: ERROR: name 'URLError' is not defined

In addition when the communication failure occurs, this adds specific failure notice to ocf_exit_reason for improved troubleshooting.  Also, changes were made to exit when URLError exception is encountered as currently the response is read into the variable data when response is null: 
ERROR: local variable 'data' referenced before assignment.

First commit here so hopefully I'm following  the right procedure… Thanks.

-Rich