git.c: treat RUN_SETUP_GENTLY and RUN_SETUP as mutually exclusive

This saves us a few branches when RUN_SETUP is set up.
Signed-off-by: NLuis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git.c

@@ -290,7 +290,7 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 	if (!help) {
 		if (p->option & RUN_SETUP)
 			prefix = setup_git_directory();
-		if (p->option & RUN_SETUP_GENTLY) {
+		else if (p->option & RUN_SETUP_GENTLY) {
 			int nongit_ok;
 			prefix = setup_git_directory_gently(&nongit_ok);
 		}