LU-9679 general: avoid bare return; at end of void function

Having:
   return;
}

at the end of a void function is unnecessary noise.
Where it is the *only* statement in the function, it can
be useful, so that remain unchanged.  The rest have been removed.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: If02f6f5b91d4134cf95a68ebccc83df28c360fb2
Reviewed-on: https://review.whamcloud.com/36654
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>
Reviewed-by: Ben Evans <bevans@cray.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>