Signed-off-by: NSage Weil <sage@newdream.net>

Inode cache and inode operations.  We also include routines to
incorporate metadata structures returned by the MDS into the client
cache, and some helpers to deal with file capabilities and metadata
leases.  The bulk of that work is done by fill_inode() and
fill_trace().
Signed-off-by: NSage Weil <sage@newdream.net>