doc/man: sync osd pool get/set flags in 8/ceph.rst

Add the flags listed for ceph osd pool set in ceph osd pool get.
Remove nonexistent flag debug_fake_ec_pool in ceph osd pool set.
Confirm the additions/removals from MonCommands.h.

Signed-off-by: Ville Ojamo <git2233+ceph@ojamo.eu>