remove unnecessary calls to get_augeas()
    
    There were several functions in drv_redhat.c that apparently had
    previously required an augeas object, but no longer do (if the augeas
    object was required, the return value of get_augeas() would have been
    saved, and the side effect of rereading the augeas tree from disk
    isn't needed as any subordinate function that required the augeas
    object to be up-to-date would also need to call get_augeas() in order
    to get its own pointer to the augeas object).
    
    This has no functional effect, it's just removing redundant code.