https://bugzilla.redhat.com/show_bug.cgi?id=1665553

Ceph can be mounted just like any other filesystem and in fact is
a shared and cluster filesystem. The filesystem magic constant
was taken from kernel sources as it is not in magic.h yet.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>