PIG-3520: Provide backward compatibility for PigRunner and PPNL after PIG-3419 (daijy via cheolsoo)


git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1532963 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk
Merge remote branch 'origin/trunk' into trunk-gd