zzlIsInRange() now is capable of handling empty sorted sets that may end...

zzlIsInRange() now is capable of handling empty sorted sets that may end inside the data set when loading very old RDB files produced by early-stage versions of Redis.

src/t_zset.c

@@ -504,7 +504,7 @@ int zzlIsInRange(unsigned char *zl, zrangespec *range) {
         return 0;
 
     p = ziplistIndex(zl,-1); /* Last score. */
-    redisAssert(p != NULL);
+    if (p == NULL) return 0; /* Empty sorted set */
     score = zzlGetScore(p);
     if (!zslValueGteMin(score,range))
         return 0;