[GFS2] [-mm patch] fs/gfs2/: possible cleanups

This patch contains the following possible cleanups:
- make needlessly global code static
- #if 0 unused functions
- remove the following global function that was both unused and
  unimplemented:
  - super.c: gfs2_do_upgrade()

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>