Ensure `git-pull` fails if `git-merge` fails.
Ensure `git-pull` fails if `git-merge` fails.

If git-merge exits with a non-zero exit status so should git-pull.
This way the caller of git-pull knows the task did not complete
successfully simply by checking the process exit status.

Signed-off-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git