fsck.gfs2: don't free prev rgrp list repairing rgrps
    
    In cases where fsck.gfs2 is trying to repair damaged resource groups or
    rindex, it tries several levels of repair.  Some of those levels build a
    list of expected resource groups and check them against the actual ones,
    and the previous list is freed before the next level is attempted.
    However, in the case of minor damage, such as one bitmap block that was
    overwritten, we can often repair the damage by reading in the resource
    groups at the first level, then at the second level of repair (called
    "ye_of_little_faith") use those values to compare against.  This patch
    allows the second level of repair to use the first level's list.
    
    rhbz#675723