test-uuid: fix leak

ASAN spotted:
SUMMARY: AddressSanitizer: 74 byte(s) leaked in 2 allocation(s).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20161109110210.25925-1-marcandre.lureau@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>

tests/test-uuid.c

@@ -161,6 +161,7 @@ static void test_uuid_unparse_strdup(void)
         }
         out = qemu_uuid_unparse_strdup(&uuid_test_data[i].uuid);
         g_assert_cmpstr(uuid_test_data[i].uuidstr, ==, out);
+        g_free(out);
     }
 }