Remove trailing backtick
Remove trailing backtick

This patch is removing a trailing backtick (`) from the
doc/running-tests.rst document.

Change-Id: Ib74c43288d269b36113812c91e47db4b0deb1d4b

stackforge/kolla,openstack/kolla,intel-onp/kolla,stackforge/kolla,coolsvap/kolla,mrangana/kolla,GalenMa/kolla,rahulunair/kolla,nihilifer/kolla,openstack/kolla,coolsvap/kolla,intel-onp/kolla,GalenMa/kolla,stackforge/kolla,nihilifer/kolla,mrangana/kolla,rahulunair/kolla,coolsvap/kolla