Add required QHash header to mmk plugin.
Add required QHash header to mmk plugin.

Change-Id: I05ae0be5a29b9d95fcb7cfa2a51b969b464adc10
Reviewed-by: Rohan McGovern <d75463945f40a9669160a73cef2843e56b22c602@nokia.com>

maui-packages/qtfeedback,maui-packages/qtfeedback