Remove extraneous vim configuration comments

Remove vim setting:
comment - # vim: tabstop=4 shiftwidth=4 softtabstop=4

at the top of source code files, except for files in
openstack/common.

Change-Id: I9a5c6b17c6ef7ecec601f4503dfc7b31fc72e90a
Close-bug: #1229324
Merge "Remove extraneous vim configuration comments"