rgmanager: Don't exit uncleanly when cman asks us to shut down.
    
    Original patch from Lon rediffed to apply to the current tree:
    
    "Previous to this, rgmanager would uncleanly exit if you
    issued a 'service cman stop'.  This patch makes it uncleanly
    exit if 'cman_tool leave force' or a corosync/openais crash
    occurs, but in a simple cman_tool leave, rgmanager will no
    longer exit uncleanly."
    
    Without this patch, issuing 'service cman stop' when rgmanager
    is running will make it impossible to stop the cman service because
    rgmanager will have exited without releasing its dlm lockspace.
    
    This patch causes rgmanager to refuse shutdown when requested
    by cman. Users must stop the rgmanager service before stopping
    the cman service.
    
    Acked-by: Fabio M. Di Nitto <fdinitto@redhat.com>
    Signed-off-by: Ryan McCabe <rmccabe@redhat.com>