fsck.gfs2 segfaults if journals are missing
    
    This patch makes it possible for fsck.gfs2 to detect missing and damaged
    journals and recreate them.  Previous versions of fsck.gfs2 would
    segfault if journals were missing because it made assumptions about
    the jindex file pointing to a valid dinode.  Also, I moved function
    ji_update which was exclusively used by fsck.gfs2 from libgfs2 to fsck.
    
    rhbz#620384