Jruby.home not working with jruby 1.6 and WebSphere

We upgraded to jruby 1.6 and after deploying our app to WebSphere, it
wouldn’t start. The problem we discovered is jruby.home is not correct.
It shows up in the logs as:

jruby.home: C:\WebSphere\AppServer\profiles\AppSrv01\logs

This path is used later in the start process and we get path not found

What should be the correct value for jruby.home?

Assuming this a bug, is there a way to manually set the variable with
the correct value?

This worked prior to 1.6.

Our app will deploy and run using WAS CE (which is Tomcat)