[PATCH v3] git cherry-pick: Add NULL check to sequencer parsing of HEAD

[Neil Horman <nhorman@tuxdriver.com>]

Michael Mueller noted that a feature I recently added failed to check the return
of lookup_commit to ensure that it was not NULL.  I don't think a NULL can
actually happen in the this particular use case, but regardless it seems a good
idea to check.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
---
 sequencer.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/sequencer.c b/sequencer.c
index f83cdfd..f7eac1d 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -261,9 +261,9 @@ static int is_index_unchanged(void)
 		return error(_("Could not resolve HEAD commit\n"));
 
 	head_commit = lookup_commit(head_sha1);
-	if (!head_commit || parse_commit(head_commit))
-		return error(_("could not parse commit %s\n"),
-			     sha1_to_hex(head_commit->object.sha1));
+
+	if (parse_commit(head_commit))
+		return -1;
 
 	if (!active_cache_tree)
 		active_cache_tree = cache_tree();
-- 
1.7.7.6