Updating to the following SimplePush version that removes the netty subsystem and uses a SimplePush specific subsystem instead. Updating the standalone.xml file accordingly and no longer adding the netty module.

SimplePush:
https://github.com/aerogear/aerogear-simplepush-server/commit/b7e531074d57e4d71850fa03b999567028a93b25
Updating UnifiedPush to the following version:

https://github.com/aerogear/aerogear-unifiedpush-server/commit/552a870bb2023f1004cc0455c0637ea975c3f46c