many: fix remaining check-pointer-deref issues

The updated parsing_hacks.h file uncovered a bunch of extra
things that the check-pointer-deref coccinelle script flags.

This commit fixes them to make the tree check-pointer-deref clean.

src/basic/fileio.c

@@ -1370,6 +1370,8 @@ int read_timestamp_file(const char *fn, usec_t *ret) {
         uint64_t t;
         int r;
 
+        assert(ret);
+
         r = read_one_line_file(fn, &ln);
         if (r < 0)
                 return r;