Initialize lock_file struct to all zero.

hold_lock_file_for_update() relies on that.
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

builtin-update-index.c

@@ -490,7 +490,7 @@ int cmd_update_index(int argc, const char **argv, char **envp)
 	git_config(git_default_config);
 
 	/* We can't free this memory, it becomes part of a linked list parsed atexit() */
-	lock_file = xmalloc(sizeof(struct lock_file));
+	lock_file = xcalloc(1, sizeof(struct lock_file));
 
 	newfd = hold_lock_file_for_update(lock_file, get_index_file());
 	if (newfd < 0)

builtin-write-tree.c

@@ -16,7 +16,7 @@ int write_tree(unsigned char *sha1, int missing_ok, const char *prefix)
 	int entries, was_valid, newfd;
 
 	/* We can't free this memory, it becomes part of a linked list parsed atexit() */
-	struct lock_file *lock_file = xmalloc(sizeof(struct lock_file));
+	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 
 	newfd = hold_lock_file_for_update(lock_file, get_index_file());