tree-wide: do not wrap assert_se in extra parentheses

We were inconsitently using them in some cases, but in majority not.
Using assignment in assert_se is very common, not an exception like in
'if', so let's drop the extra parens everywhere.

src/test/test-dlopen.c

@@ -13,7 +13,7 @@
 int main(int argc, char **argv) {
         void *handle;
 
-        assert_se((handle = dlopen(argv[1], RTLD_NOW)));
+        assert_se(handle = dlopen(argv[1], RTLD_NOW));
         assert_se(dlclose(handle) == 0);
 
         return EXIT_SUCCESS;