Remove some leftover includes of QRegExp

and include qrefularexpression.h in the pch for Qt Core.

Change-Id: Ibfa84c911dfcffd3e5a5cf11e48b186cff6e7d7a
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

src/corelib/global/qt_pch.h

@@ -69,7 +69,7 @@
 #include <qlist.h>
 #include <qvariant.h>  /* All moc genereated code has this include */
 #include <qobject.h>
-#include <qregexp.h>
+#include <qregularexpression.h>
 #include <qscopedpointer.h>
 #include <qshareddata.h>
 #include <qstring.h>

src/corelib/itemmodels/qabstractitemmodel.cpp

@@ -45,7 +45,6 @@
 #include <qmimedata.h>
 #include <qdebug.h>
 #include <qvector.h>
-#include <qregexp.h>
 #if QT_CONFIG(regularexpression)
 #  include <qregularexpression.h>
 #endif