remove some unnecessary CONFIG additions

qt is already added by spec_pre.prf.

Change-Id: Id53efb418c1d545c4c90280f54b3824ae8261e49
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

examples/activeqt/hierarchy/hierarchy.pro

 TEMPLATE = lib
 TARGET	 = hierarchyax
 
-CONFIG += qt warn_off dll
+CONFIG += warn_off dll
 QT += widgets axserver
 
 SOURCES	 = objects.cpp main.cpp

examples/activeqt/menus/menus.pro

 TEMPLATE = app
 TARGET	 = menusax
 
-CONFIG += qt warn_off
+CONFIG += warn_off
 QT += widgets axserver
 
 SOURCES	 = main.cpp menus.cpp

examples/activeqt/multiple/multiple.pro

 TEMPLATE = lib
 TARGET	 = multipleax
 
-CONFIG += qt warn_off dll
+CONFIG += warn_off dll
 QT += widgets axserver
 
 SOURCES	 = main.cpp

examples/activeqt/opengl/opengl.pro

 TEMPLATE = app
 TARGET	 = openglax
 
-CONFIG += qt warn_off
+CONFIG += warn_off
 QT += widgets axserver opengl
 
 HEADERS	 = glbox.h \

examples/activeqt/simple/simple.pro

 TEMPLATE = app
 TARGET	 = simpleax
 
-CONFIG += qt warn_off
+CONFIG += warn_off
 QT += widgets axserver
 
 SOURCES	 = main.cpp

examples/activeqt/wrapper/wrapper.pro

 TEMPLATE = lib
 TARGET	 = wrapperax
 
-CONFIG += qt warn_off dll
+CONFIG += warn_off dll
 QT += widgets axserver
 
 SOURCES	 = main.cpp