OOZIE-1322 show child job URL tab selectively for pig action (ryota via mona)

git-svn-id: https://svn.apache.org/repos/asf/oozie/trunk@1468286 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-YAHOO-306-trunk-gd