gfs2_edit: add -d option for printing journal details
    
        This patch adds a new parameter "-d" to gfs2_edit.  If -d is specified,
        printing a journal will dump the details of the metadata blocks contained
        in the journal, as well as the usual log descriptors and log headers.
        This makes it easier to find dinode revisions in the journal.
    
        rhbz#674843