Ignore empty log translation source files
Ignore empty log translation source files

We do not need to store any empty source translation files in git or in
Zanata. There are many empty LOG source translation files, so let's
remove them.

Note we always keep the "main" files, the "main" files should always
have content.

The change tests after generation of LOG source translation files
whether these are empty and deletes them from filesystem and git.

Change-Id: I0957c66fca5aa5ded93c858766a4c0a93f963032

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