HyperLogLog: fix the fix of a corruption bug.

src/hyperloglog.c

@@ -700,8 +700,7 @@ int hllSparseSet(robj *o, long index, uint8_t count) {
         p += oplen;
         first += span;
     }
-    if (span == 0) return -1; /* Invalid format. */
-    if (span >= end) return -1; /* Invalid format. */
+    if (span == 0 || p >= end) return -1; /* Invalid format. */
 
     next = HLL_SPARSE_IS_XZERO(p) ? p+2 : p+1;
     if (next >= end) next = NULL;