There is dependency compatibility issue. Currently hadoop-2.6.0 use 1.9.13 for jackson. Upgrade to the same version to make it consistent.

Author: Zhan Zhang <zhazhan@gmail.com>

Closes #3938 from zhzhan/spark5108 and squashes the following commits:

0080a84 [Zhan Zhang] change to upgrade jackson version only in hadoop-2.x
0b9bad6 [Zhan Zhang] Merge branch 'master' of https://github.com/apache/spark into spark5108
917600a [Zhan Zhang] solve conflicts
f7064d0 [Zhan Zhang] hadoop2.6 dependency management fix
fc56b25 [Zhan Zhang] squash all commits
3bf966c [Zhan Zhang] test