svcrdma: Clean up process_context()

Be sure the completed ctxt is put in every path.

The xprt enqueue can take a while, so put the completed ctxt back
in circulation _before_ enqueuing the xprt.

Remove/disable debugging.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>