Fixed -dbus-linked when cross-compiling from Windows

Since Windows doesn't have pkg-config, it doesn't get -ldbus-1
added to the command line automatically like Linux does.  Code
was present to deal with this case, however it was only configured
to work when native-compiling Qt.  The flag was not added when
cross-compiling, meaning that -dbus-linked did not work correctly
in that case.  This patch changes the code to add the flag properly
in both cases.

Change-Id: I67881643bd658161f4929f3932859ccf636ca7a9
Task-number: QTBUG-29984
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/dbus/dbus.pro

@@ -6,6 +6,8 @@ MODULE_CONFIG = dbusadaptors dbusinterfaces
 !isEmpty(DBUS_PATH) {
     INCLUDEPATH += $$DBUS_PATH/include
     QMAKE_LIBDIR += $$DBUS_PATH/lib
+    win32:CONFIG(debug, debug|release):QT_LIBS_DBUS += -ldbus-1d
+    else:QT_LIBS_DBUS += -ldbus-1
 }
 
 DEFINES += DBUS_API_SUBJECT_TO_CHANGE
@@ -21,8 +23,6 @@ win32 {
         -ladvapi32 \
         -lnetapi32 \
         -luser32
-    CONFIG(debug, debug|release):LIBS_PRIVATE += -ldbus-1d
-    else:LIBS_PRIVATE += -ldbus-1
 }
 
 QMAKE_DOCS = $$PWD/doc/qtdbus.qdocconf