Utils: Remove qPidToPid() adapter function

Since Qt 5.3, there's a QProcess::processId() providing direct access.

Change-Id: Ia9c143c7a92ec61d1aa36ff3f4670ba72a509634
Reviewed-by: Tim Jenssen <tim.jenssen@theqtcompany.com>
Reviewed-by: David Schulz <david.schulz@theqtcompany.com>

src/libs/utils/qtcprocess.h

@@ -157,10 +157,6 @@ private:
     bool m_useCtrlCStub;
 };
 
-// Converts the Q_PID into a integer value. This is a no-op
-// except on Windows.
-QTCREATOR_UTILS_EXPORT unsigned long qPidToPid(const Q_PID qpid);
-
 } // namespace Utils
 
 #endif // QTCPROCESS_H