srm: Fix regression in srmCopy

CopyRequest and CopyFileRequest are both processed by the
same SRM scheduler. Thus the scheduler must be configured
for a common base class of these two jobs.

Target: trunk
Request: 2.7
Require-notes: no
Require-book: no
Acked-by: Paul Millar <paul.millar@desy.de>
Acked-by: Dmitry Litvintsev <litvinse@fnal.gov>
Patch: http://rb.dcache.org/r/5996/
(cherry picked from commit a4ce5adfa8e080a3999b9c6243a6857486e6d564)