Remove extjs From Oozie Installations By Default

GPL code was recently removed from some repositories, such as HDP-UTILS. Oozie uses a GPL module called extJS which is installed by default with no option not to install it.

2017-11-28 17:00:17,813 - Execution of '/usr/bin/yum -d 0 -e 0 -y install extjs' returned 1. Error: Nothing to do
2017-11-28 17:00:17,814 - Failed to install package extjs. Executing '/usr/bin/yum clean metadata'
2017-11-28 17:00:18,075 - Retrying to install package extjs after 30 seconds

Since it no longer is included in the repos, it should be removed. Oozie can still load and start without it, but the web client will not be available.