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.

Change-Id: I1f825add9036623ef626b48c66206ac2b452c592
Partial-Bug: #1262424
Drop indexing operator from linear flow

It is not needed. Also, using it complicates transitioning
to another pattern (e.g. graph flow) and encourages bad
programming practices.

Change-Id: I9d0a4646a27df1a11ed436f26a0cb074b717647e
Merge "Removed copyright from empty files"
Merge "Drop indexing operator from linear flow"