[build] switch to released jnr-posix

[skip ci]
[openssl] X509 cert extension authority key identifier finally matches MRI ...
we can not guarantee extension ordering using Java APIs (otherwise this rolls fine)

... and there's the same test without the extension order passing at :
https://github.com/jruby/jruby-openssl/commit/eb30f9bd73ae25750593
WiP - do not exclude those that no longer fail ... (at least on 1.9)
test_decode_all and test_decode_pem now pass (on JRuby-OpenSSL master)
use jruby-openssl-0.9.6.dev-SNAPSHOT
get the adding pem to x509store test back
fix pem test since some are not self signed