Branch b1_4_mountconf

Branch b1_4_mountconf
b=9860
interoperability with 1.4.6:
keep old uuids but new server names when ungrading old logs -
names are local, connects all happen through uuids.
(partially hardcoded for now)
- don't change config log magic, header size
- add uuid to disk data
- copy old client and mds log from LOGS to new names under CONFIGS, MGS
  will then modify the logs.
- index number and uuid taken from last_rcvd (1.4.6)
- llog_filp_open must take directory path now (MDT will still serve old
  logs to old client from old LOGS dir.)