Add missing files to PUBLIC_HEADERS.
Add missing files to PUBLIC_HEADERS.

qmessagedatacomparator.h and qmessageglobal.h are included by public
headers but weren't listed in the pro file. This meant that building
applications against an installed messaging would fail.

Reviewed-by: owolff

tmcguire/qt-mobility,enthought/qt-mobility,enthought/qt-mobility,enthought/qt-mobility,tmcguire/qt-mobility,qtproject/qt-mobility,KDE/android-qt-mobility,enthought/qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,kaltsi/qt-mobility,KDE/android-qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,KDE/android-qt-mobility,kaltsi/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,KDE/android-qt-mobility,qtproject/qt-mobility