[GFS2] Remove unused counters

This is kind of trivial in the greater scheme of things, but
this removes three counters that AFAICT are never used.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --cc fs/gfs2/incore.h
Simple merge

diff --cc fs/gfs2/sys.c
Simple merge