Wrong values in mkspec\default\qmake.conf with MSVC2010 build

default\qmake.conf's QMAKESPEC_ORIGINAL value contains the source directory path, but it should point to the installation path.

This is correct in Qt5beta1 binary package, but wrong in manual build.

E.g. it contains

QMAKESPEC_ORIGINAL = C:/WebKitBuildSlave/Qt5.0.0-r38-source/qt5/qtbase/mkspecs/win32-msvc2010
include($$QMAKESPEC_ORIGINAL/qmake.conf)

but Qt is configured with "-prefix C:\WebKitBuildSlave\Qt5.0.0-r38-angle", so it should be

QMAKESPEC_ORIGINAL = C:/WebKitBuildSlave/Qt5.0.0-r38-angle/qt5/qtbase/mkspecs/win32-msvc2010
include($$QMAKESPEC_ORIGINAL/qmake.conf)

There is also an other problem with this qmake.conf. After the change
http://qt.gitorious.org/qt/qtbase/commit/0fae8b50f7c37fad7f93845495199891d6191291/diffs
WebKit can't resolve the include path. This is necessary for nmake detection.

Also there is an old bug
https://bugreports.qt-project.org/browse/QTBUG-16172
that said

mkspecs/default/qmake.conf shouldn't use absolute path in the include statement because this will break for Qt binary deployments that cannot patch this file at the installation time, such as internal Symbian SDK deployments that include Qt.

It was just fine as

include(../win32-msvc2010/qmake.conf)