Prevent garbage from readline on standard output of dogtag-ipa-retrieve-agent.

https://fedorahosted.org/freeipa/ticket/4064
Increase Java stack size on s390 platforms

As reported in https://bugzilla.redhat.com/show_bug.cgi?id=1040576,
the default stack trace needs to be also increased on s390 platforms
to prevent rhino segfault.