LU-7736 scripts: ensure lustre_rmmod unload all modules

LU-7736 scripts: ensure lustre_rmmod unload all modules

The luste_rmmod script unloads the lustre modules recursively from
libcfs, unloading each dependent module first.

If the module dependency order makes an LND module to be unloaded
before the ptlrpc module, the LND unload fails and it results in
lnet and libcfs modules still loaded at the end.

	# modprobe lustre
	# lctl list_nids
	10.1.0.64@o2ib
	# lustre_rmmod
	Modules still loaded:
	lnet/lnet/lnet.o libcfs/libcfs/libcfs.o

This patch ensures modules are all unloaded by the lustre_rmmod
script.

Signed-off-by: Gregoire Pichon <gregoire.pichon@bull.net>
Change-Id: Id94308332a4f5f95f4617f0d5882a9e2857ee20d
Reviewed-on: http://review.whamcloud.com/18279
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Frederic Saunier <frederic.saunier@atos.net>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>