check availability of qmldevtools, not declarative

that's the module we actually use

Change-Id: I928778a8638a8d0b2022696120dcaf6aa28a9d6d
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/linguist/lupdate/lupdate.pro

@@ -2,7 +2,7 @@ DESTDIR = $$QT.designer.bins
 
 QT = core-private
 
-!isEmpty(QT.declarative.name) {
+!isEmpty(QT.qmldevtools.name) {
     QT += qmldevtools-private
 } else {
     DEFINES += QT_NO_QML
@@ -22,7 +22,7 @@ SOURCES += \
     java.cpp \
     ui.cpp
 
-!isEmpty(QT.declarative.name): SOURCES += qdeclarative.cpp
+!isEmpty(QT.qmldevtools.name): SOURCES += qdeclarative.cpp
 
 HEADERS += \
     lupdate.h \