Branch b1_4_mountconf

Branch b1_4_mountconf
b=8007
Kick the mgs import a little harder.  If an mgs/mdt was restarted on a node
with a live mgc, the mgc wouldn't reconnect to the newly restarted
mgs. Throwing the ptlrpc_invalidate_import in there gives it a little more
incentive to reconnect - the mgs mount still gets EIO the first time, but
if you try it again it works.  I need help from somebody with more
knowledge of all these ptlrpc_ fns.