Grow.c: fix uninitialized variables compilation-time error

Grow.c: fix uninitialized variables compilation-time error

It fixes the following uninitialized variables compilation-time error:
WARN  - Grow.c: In function ‘reshape_array’:
WARN  - Grow.c:2413:21: error: ‘min_space_after’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
WARN  - Grow.c:2376:39: note: ‘min_space_after’ was declared here
WARN  - Grow.c:2414:22: error: ‘min_space_before’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
WARN  - Grow.c:2376:21: note: ‘min_space_before’ was declared here
WARN  - cc1: all warnings being treated as errors
WARN  - make: *** [Grow.o] Error 1
It occurs during compilation of mdadm on Fedora 17.

Signed-off-by: Lukasz Dorau <lukasz.dorau@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>