receive-pack: call setup_ident before git_config

Otherwise we would end up getting values from Gecos which is often not
what people would want.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

receive-pack.c

@@ -261,6 +261,7 @@ int main(int argc, char **argv)
 	if (!enter_repo(dir, 0))
 		die("'%s': unable to chdir or not a git archive", dir);
 
+	setup_ident();
 	git_config(git_default_config);
 
 	write_head_info();