ceph.spec.in: Don't use noarch for ceph-mgr module subpackages

ceph.spec.in: Don't use noarch for ceph-mgr module subpackages

Even though ceph-mgr modules are notionally non-architecture-specific,
the files themselves are installed to an architecture-specific path
(/usr/lib64/ceph/mgr/....), which causes the build to fail on SUSE
distros with a huge long list of errors like:

ceph-mgr-diskprediction-cloud.noarch: E: suse-filelist-forbidden-noarch
(Badness: 10000) /usr/lib64/ceph/mgr/diskprediction_cloud is not
allowed in a noarch package
[...]
(none): E: badness 1120287 exceeds threshold 1000, aborting.

Signed-off-by: Tim Serong <tserong@suse.com>