Handle missing pot files in translation proposal
Handle missing pot files in translation proposal

searchlight project had only one pot file but not the other five that
are expected. The filter_commit function was filtering out the newly
added file and run "git checkout -- NEWFILE" which failed.

Make the script more robust so that it handles newly added files
correctly.

Change-Id: I4a7a8ab9b75f310992b7232920206d4ddc041268

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