Revert "mds: disable delegating inode ranges to clients"

Revert "mds: disable delegating inode ranges to clients"

This isn't necessary -- the MDS handles delegating inode ranges
to clients from its preallocated inode set properly - the suspected
bug involving not persisting the sessionmap and causing asserts
during replay isn't an issue. The preallocated set is persisted
with the log event and the MDS correctly rebuild the set from
this information during replay.

Signed-off-by: Venky Shankar <vshankar@redhat.com>