builtin-merge.c: call exclude_cmds() correctly.

We need to call exclude_cmds() after the loop, not during the loop, because
excluding a command from the array can change the indexes of objects in the
array.  The result is that, depending on file ordering, some commands
weren't excluded as they should have been.

Signed-off-by: Avery Pennarun <apenwarr@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-merge.c

@@ -106,8 +106,8 @@ static struct strategy *get_strategy(const char *name)
 					found = 1;
 			if (!found)
 				add_cmdname(&not_strategies, ent->name, ent->len);
-			exclude_cmds(&main_cmds, &not_strategies);
 		}
+		exclude_cmds(&main_cmds, &not_strategies);
 	}
 	if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
 		fprintf(stderr, "Could not find merge strategy '%s'.\n", name);