staging: lustre: fix all conditional comparison to zero for kernelcomm.c

Doing if (rc != 0) or if (rc == 0) is bad form. This patch corrects
kernelcomm.c to behavior according to kernel coding standards.

Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>