Ensure fast-POST operations are used on objects

The defacto swift implementation has a feature called "fast-POSTs",
which is an optimization that allows POST operations on files to be
performed by updating metadata on additional .meta files. The default
is to treat all POST opreations as a COPY operation. Since this
gluster-swift code stores all metadata directly on the original object
file, there is no need to use an inefficient operation such as COPY.

BUG XXXXXX: (https://bugzilla.redhat.com/show_bug.cgi?id=XXXXXX)

Change-Id: I39f0a682d5344c3f84c5baa8e292227051c061b8
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Reviewed-on: http://review.gluster.org/5673
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>