Update Horizon English message files for translation

Generated the latest version of three English message files based on
the current code base, for syncronizing with resources in Transifex.

Strings from openstack/common are excluded.
Update script: run_tests.sh to exclude strings from openstack/common

Change-Id: I1aeb990bf472eaac03734b42452e42d33f9168c6
Merge "Update Horizon English message files for translation"