client: do not check file size when inode does not have Fc caps

client: do not check file size when inode does not have Fc caps

Since the client is holding Fr caps, the read request can be
directly sent to the OSD. The offset/in->size comparison check
is causing the read request to return with no data since in->size
isn't yet updated when another client does an extending write.

Introduced-by: 942474c2f5b4c696364f3b7411ae7d96444edfa8
Fixes: http://tracker.ceph.com/issues/70726
Signed-off-by: Venky Shankar <vshankar@redhat.com>