Ceph: remove left-over reject file

Neither Sage nor I noticed that Zheng Yan had mistakenly committed
fs/ceph/super.h.rej as part of commit 31c542a199d7 ("ceph: add inline
data to pagecache").

Remove it.

Requested-by: Yan, Zheng <ukernel@gmail.com>
Cc: Sage Weil <sweil@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>