adjust to qt_plugin.prf changes

DESTDIR and INSTALLS+=target are set up automatically now, but
PLUGIN_TYPE needs to be defined.

Change-Id: I82a97498be26a6e9021deb6fff02a21bd4787851
Reviewed-by: Andy Nichols <andy.nichols@digia.com>

src/plugins/platforms/wayland/wayland.pro

@@ -1,10 +1,10 @@
 TARGET = qwayland
+
+PLUGIN_TYPE = platforms
 load(qt_plugin)
 
 CONFIG += link_pkgconfig qpa/genericunixfontdatabase
 
-DESTDIR = $$QT.compositor.plugins/platforms
-
 QT += core-private gui-private platformsupport-private
 
 SOURCES =   main.cpp \
@@ -86,9 +86,6 @@ INCLUDEPATH += $$PWD/../../../shared
     LIBS += -lwayland-client
 }
 
-target.path += $$[QT_INSTALL_PLUGINS]/platforms
-INSTALLS += target
-
 include ($$PWD/gl_integration/gl_integration.pri)
 include ($$PWD/windowmanager_integration/windowmanager_integration.pri)