Clang: Improve interfaces

The interfaces should never used to handle ownership. So it is now using
protected destructors. Copy operations are forbidden too.

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c35-a-base-class-destructor-should-be-either-public-and-virtual-or-protected-and-nonvirtual

Change-Id: Ib0b60a73a7ec130973b5cb0095cc5b2f10fa0758
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/libs/sqlite/sqlitedatabase.h

@@ -55,10 +55,7 @@ public:
     Database(Utils::PathString &&databaseFilePath, JournalMode journalMode=JournalMode::Wal);
 
     Database(const Database &) = delete;
-    bool operator=(const Database &) = delete;
-
-    Database(Database &&) = delete;
-    bool operator=(Database &&) = delete;
+    Database &operator=(const Database &) = delete;
 
     void open();
     void open(Utils::PathString &&databaseFilePath);