Add common exclusion for Zanata openstack-manuals
Add common exclusion for Zanata openstack-manuals

*/source/common in the openstack-manuals repository is a symbolic
link to common-rst, which results in pushing the files twice, and
may result in confusion. Add that path to the excludes for
openstack-manuals only.

Change-Id: I6067d94d71d3d025fc81cf331c84d5b214752218

Tesora/tesora-project-config,openstack-infra/project-config,noorul/os-project-config,dongwenjuan/project-config,dongwenjuan/project-config,openstack-infra/project-config,Tesora/tesora-project-config,noorul/os-project-config