Don't run the package in the ubuntu1804 build image

ffmpeg/Makefile

@@ -8,7 +8,8 @@ ffmpeg:
 	git clone git://source.ffmpeg.org/ffmpeg.git
 
 	bash ../ubuntu1804.sh make ffmpeg_impl
-	bash ../ubuntu1804.sh make package
+
+	make package
 
 ffmpeg_impl:
 	apt-get update