gfs2_edit: Don't prematurely release buffer_heads
    
    save_indirect_blocks() currently releases buffer_heads which should be left
    queued to save off later. This patch, backported from commit d8c8af9 upstream,
    leaves them on the queue to avoid corruption.
    
    Resolves: rhbz#698298
    
    Signed-off-by: Andrew Price <anprice@redhat.com>