Sqlite: Add swap for ConstIterator

Otherwise we get an recursion.

Change-Id: Ia8dfcbeae30b25d9d347404ae85b852c4c11c921
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/sqlite/sqlitesessionchangeset.h

@@ -147,13 +147,19 @@ public:
     ConstIterator &operator=(ConstIterator &&other)
     {
         auto tmp = std::move(other);
-        std::swap(tmp, *this);
+        swap(tmp, *this);
 
         return *this;
     }
 
     ~ConstIterator();
 
+    friend void swap(ConstIterator &first, ConstIterator &second)
+    {
+        std::swap(first.m_sessionIterator, second.m_sessionIterator);
+        std::swap(first.m_state, second.m_state);
+    }
+
     ConstIterator &operator++();
 
     friend bool operator==(const ConstIterator &first, const ConstIterator &second)