gfs2: be more verbose replaying invalid rgrp blocks

This patch adds some crucial information when journal replay detects a
replay of an obsolete rgrp block. For example, it wasn't printing the
journal id or the generation number played. This just supplements what
is logged in this unusual case.

The function that actually complains about the replaying of an obsolete
rgrp block has been split off to avoid long lines and sparse warnings.

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