restore_env(): free the saved environment variable once we are done

Just like we free orig_cwd, which is the value of the original
working directory saved in save_env_before_alias(), once we are
done with it, the contents of orig_env[] array, saved in the
save_env_before_alias() function should be freed; otherwise,
the second and subsequent calls to save/restore pair will leak
the memory allocated in save_env_before_alias().

Signed-off-by: Junio C Hamano <gitster@pobox.com>

git.c

@@ -54,10 +54,12 @@ static void restore_env(int external_alias)
 		if (external_alias &&
 		    !strcmp(env_names[i], GIT_PREFIX_ENVIRONMENT))
 			continue;
-		if (orig_env[i])
+		if (orig_env[i]) {
 			setenv(env_names[i], orig_env[i], 1);
-		else
+			free(orig_env[i]);
+		} else {
 			unsetenv(env_names[i]);
+		}
 	}
 }