rgmanager: fix nfsrestart option to be effective
    
    The original patch e512a9ce367 was still racy in some conditions
    as other rpc.* and nfs* processes were holding a lock on the filesystem.
    
    stopping nfs in kernel is simply not enough in rhel5
    
    this fixed version does stop nfs completely and re-instante nfs exports.
    
    Resolves: rhbz#822066
    
    Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>
    Acked-by: Lon Hohberger <lhh@redhat.com>