LU-13595 scripts: Add a debug option to lustre_rmmod

LU-13595 scripts: Add a debug option to lustre_rmmod

The option is "-d" or "--debug-kernel", it uses "lctl debug_kernel" to
get debug message before unload libcfs.
For each module the script add a debug mark before unloading.

Example:
	$ lustre_rmmod -d > /tmp/lustre_rmmod.log
	$ lustre_rmmod -d lustre lnet > /tmp/lustre_rmmod2.log

Test-Parameters: trivial
Signed-off-by: Etienne AUJAMES <eaujames@ddn.com>
Change-Id: I6e44a24f2e786c08faf1db27de94e0f88ca65dc7
Reviewed-on: https://review.whamcloud.com/38941
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Olaf Faaland-LLNL <faaland1@llnl.gov>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>