Revert "GFS2: free disk inode which is deleted by remote node -V2"

This reverts commit 970343cd ("GFS2: free disk inode which is
deleted by remote node -V2").

The original intent behind commit 970343cd was to cull dentries when a
remote node requests to demote an iopen glock, which happens when the
remote node tries to delete the inode.  This is now handled by
gfs2_try_evict(), which is called via iopen_go_callback() ->
gfs2_queue_try_to_evict().

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>