PIG-3305: Infinite loop when input path contains empty partition directory

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1478451 13f79535-47bb-0310-9956-ffa450edef68
PIG-3097: HiveColumnarLoader doesn't correctly load partitioned Hive table

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1478463 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk