TEZ-1643. DAGAppMaster kills DAG & shuts down, when RM is restarted. (hitesh)

(cherry picked from commit e9208c0808c2a0649ce336d87534ad6f9cbab818)
TEZ-1684. upgrade mockito to latest release  (Rajesh Balamohan)
(Cherry picked from commit 6bc134837915ebe78ed77f02579a92a7d4d4cb40)
TEZ-1567. Avoid blacklisting nodes when the disable blacklisting
threshold is about to be hit. (sseth)
(cherry picked from commit e530a46c352234459d2aced93e43fcb83c98d450)
TEZ-1267. Exception handling for VertexManager (zjffdu)

(cherry picked from commit b4674b485dd4e62c177d87581f302b243f24d797)
TEZ-1695. Set correct version on 0.5 branch to 0.5.2-SNAPSHOT. (hitesh)