Clarify a pointers value for FlexeLint

bin/varnishd/cache_dir_random.c

@@ -90,7 +90,7 @@ vdi_random_getfd(const struct director *d, struct sess *sp)
 	struct vbc *vbe;
 	struct director *d2;
 	struct SHA256Context ctx;
-	uint8_t sign[SHA256_LEN], *hp;
+	uint8_t sign[SHA256_LEN], *hp = NULL;
 
 	CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
 	CHECK_OBJ_NOTNULL(d, DIRECTOR_MAGIC);
@@ -128,6 +128,7 @@ vdi_random_getfd(const struct director *d, struct sess *sp)
 	 * amongst the healthy set.
 	 */
 	if (vs->criteria != c_random) {
+		AN(hp);
 		u = vle32dec(hp);
 		r = u / 4294967296.0;
 		assert(r >= 0.0 && r < 1.0);