LU-3042 build: fix 'NULL pointer dereference' errors

LU-3042 build: fix 'NULL pointer dereference' errors

Fix 'NULL pointer dereference' defects found by Coverity version
6.5.0:
Dereference after null check (FORWARD_NULL)
For instance, Passing null pointer to a function which dereferences
it.
Dereference before null check (REVERSE_INULL)
Null-checking variable suggests that it may be null, but it has
already been dereferenced on all paths leading to the check.
Dereference null return value (NULL_RETURNS)

Signed-off-by: Sebastien Buisson <sebastien.buisson@bull.net>
Signed-off-by: James Nunez <james.a.nunez@intel.com>
Change-Id: Ie04698f49ec7804466962511e3035c00b14b3d8c
Reviewed-on: http://review.whamcloud.com/5868
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>