fix pending operation cleanup

LeStorage/PendingOperationManager.swift

@@ -11,7 +11,7 @@ class PendingOperationManager<T: Storable> {
     
     fileprivate(set) var items: [PendingOperation<T>] = []
 
-    fileprivate var _fileName: String = "pending_\(T.resourceName())"
+    fileprivate var _fileName: String = "pending_\(T.resourceName()).json"
     
     fileprivate var _inMemory: Bool = false
     

LeStorage/StoredCollection.swift

@@ -486,6 +486,7 @@ public class StoredCollection<T: Storable>: SomeCollection {
             
             self._delegate?.itemMerged(item)
         }
+        manager.reset()
         
         self.pendingOperationManager = nil
     }