OOZIE-1177 HostnameFilter should only catch UnknownHostException, not Exception (rkanter)

git-svn-id: https://svn.apache.org/repos/asf/oozie/trunk@1434977 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of github.com:griddynamics/oozie into trunk-gd