hammer2 - Refactor frontend part 8/many

hammer2 - Refactor frontend part 8/many

* Continue work to consolidate master copy of node-independent inode
  meta-data into ip->meta.  Use ip->meta as the master (there may still
  be a few places where that isn't happening).

* Remove related cluster ops when not needed.  Includes vop_getattr,
  vop_setattr.

* Remove bogus clearing of HAMMER2_INODE_MODIFIED outside of
  hammer2_inode_fsync().

* Better handling of the HAMMER2_INODE_RESIZED flag.  Also optimize the
  standard extension case when not crossing the DIRECTDATA boundary by
  not setting the flag.  e.g. most write-append cases.