Fix lock store bug.

Summary: Lock store was not locking properly. It created a lock object which was destructed in the end of function scope which caused bits to be set to UNLOCKED.

Reviewers: matej.gradicek, buda

Reviewed By: matej.gradicek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D154

src/transactions/lock_store.hpp

@@ -39,11 +39,11 @@ class LockStore {
  public:
   template <class... Args>
   void take(T *lock, Args &&... args) {
-    auto holder = LockHolder(lock, std::forward<Args>(args)...);
-
-    if (!holder.active()) return;
-
     locks.emplace_back(LockHolder(lock, std::forward<Args>(args)...));
+    if (!locks.back().active()) {
+      locks.pop_back();
+      return;
+    }
   }
 
  private: