pass a pointer instead of a reference to initFrom()

msvc thinks that it's impossible to create a null reference (because
some language lawyer said so) and thus complains about our assert that
checks the reference's validity. work around by not dereferencing the
pointers we already have.

Change-Id: Ife2288d4187860105de12fdebc0e671e0159ace3
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

qmake/project.cpp

@@ -60,7 +60,7 @@ QMakeProject::QMakeProject()
 QMakeProject::QMakeProject(QMakeProject *p)
     : QMakeEvaluator(Option::globals, Option::parser, Option::vfs, &Option::evalHandler)
 {
-    initFrom(*p);
+    initFrom(p);
 }
 
 bool QMakeProject::boolRet(VisitReturn vr)