add jackson-core-asl 1.8.8 dependency

When I use jackson lib on spark app. to parse json string, jackson-mapper-asl 1.8.8 conflicts with jackson-core-asl (1.9.x) 
jackson-mapper-asl 1.8.8 dependency doesn't affect jackson-core-asl version.
So, I add jackson-core-asl 1.8.8 dependency to match the version of jackson-mapper-asl.
My app. is working well after fix it.