Catch Timeout on test connection

[Glutexo]

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Complete Description of Additions/Changes:

The --test-connection command only used to catch ConnectionError, including ConnectionTimeout, but not other timeouts such as ReadTimeoutError. Re-used the existing REQUEST_FAILED_EXCEPTIONS list to process all timeouts in the same way.

There is an integration test pull request https://github.com/RedHatInsights/insights-client/pull/244 for this fix.

Card IDs:

• CCT-506