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/shared/cryptsetup-util.c

@@ -214,6 +214,8 @@ int cryptsetup_get_volume_key_prefix(
         const char *uuid;
         char *s;
 
+        assert(ret);
+
         uuid = sym_crypt_get_uuid(cd);
         if (!uuid)
                 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to get LUKS UUID.");
@@ -248,6 +250,8 @@ int cryptsetup_get_volume_key_id(
         char *hex;
         int r;
 
+        assert(ret);
+
         r = cryptsetup_get_volume_key_prefix(cd, volume_name, &prefix);
         if (r < 0)
                 return log_debug_errno(r, "Failed to get LUKS volume key prefix.");