Some Qualsys results can be returned without a grade, causing an exception. #15
Description
This can happen when a domain resolves to multiple addresses, but only some of them are responsive.
My initial thought (and my fix on my own system) was just to compact ssl_grades before sorting it.
Some users might not want errors like that to be handled silently though, so I'm not sure what solution you'd want to implement.
The current behaviour though is just to throw an exception:
Check failed to run: comparison of NilClass with 7 failed, [
"/opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/sensu-plugins-ssl-1.0.0/bin/check-ssl-qualys.rb:120:in `sort_by'",
"/opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/sensu-plugins-ssl-1.0.0/bin/check-ssl-qualys.rb:120:in `sort_by!'",
"/opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/sensu-plugins-ssl-1.0.0/bin/check-ssl-qualys.rb:120:in `lowest_grade'",
"/opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/sensu-plugins-ssl-1.0.0/bin/check-ssl-qualys.rb:124:in `run'",
"/opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/sensu-plugin-1.3.0/lib/sensu-plugin/cli.rb:57:in `block in <class:CLI>'"
]