Bug 1272732 - Specifying --disable-android-apz breaks Fennec build. r=kats

gfx/layers/moz.build

@@ -254,7 +254,7 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'gonk':
         'ipc/ShadowLayerUtilsGralloc.cpp',
     ]
 
-if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'android':
+if CONFIG['MOZ_ANDROID_APZ']:
     UNIFIED_SOURCES += [
         'apz/src/FlingOverScrollerAnimation.cpp',
     ]