Removed copyright from empty files

According to policy change in HACKING:
http://docs.openstack.org/developer/hacking/#openstack-licensing
empty files should no longer contain copyright notices.
Please note, Oslo (nova/openstack/common) not changed!

Closes-bug: #1262424
Change-Id: I26b7d1eabb189f06219b70495d229389b9d3f260
Merge "Removed copyright from empty files"