Remove unused member

Change-Id: Icb404090885619f76a0a34861da8474c0f16571d
Reviewed-on: http://codereview.qt-project.org/5450

Reviewed-by: Daniel Teske <daniel.teske@nokia.com>

src/plugins/qt4projectmanager/qmakestep.h

@@ -126,7 +126,6 @@ private:
     void ctor();
 
     // last values
-    QStringList m_lastEnv;
     bool m_forced;
     bool m_needToRunQMake; // set in init(), read in run()
     QString m_userArgs;