storage: Making use of SkipList-based index

Change-Id: I360af97ae794da383fe00aaad8ab3c417c5167d3
Refs: #1695, #1434
diff --git a/src/storage/skiplist.hpp b/src/storage/skiplist.hpp
index 1243a71..34c7c57 100644
--- a/src/storage/skiplist.hpp
+++ b/src/storage/skiplist.hpp
@@ -397,7 +397,7 @@
     m_head->prevs.resize(newLevel + 1, m_head);
     insertPositions.resize(newLevel + 1, m_head);
   }
-  for (int i = 0; i <= static_cast<int>(newLevel); i++) {
+  for (int i = 0; i <= newLevel; i++) {
     newNode->nexts[i] = insertPositions[i]->nexts[i];
     newNode->prevs[i] = insertPositions[i];
     insertPositions[i]->nexts[i] = newNode;