Add and clean-up null-checks.

Change-Id: I4af4c6c3342f19cfc93a27c42ff150818c812e2b
Merge branch 'master' into nullchecks
Restore English as default language in server config page.

Add EnablePluginMessages back.

Change-Id: If791839e2982837c14578aeb08eadc7c5921e8c4
Merge pull request #85 from mathieu-wang/nullchecks

Add and clean-up null-checks.
Merge pull request #86 from mathieu-wang/fix-gerritserver-language

Restore English as default language in server config page.
More null checks