Adding bcpkix to the jclouds-sshj driver. Required by sshj.

See [JCLOUDS-452](https://issues.apache.org/jira/browse/JCLOUDS-452).

@andreaturli: Turns out sshj 0.9.0 [breaks stuff](https://issues.apache.org/jira/browse/JCLOUDS-451), so now tryng the solution you [originally suggested](https://github.com/jclouds/jclouds/pull/273#issuecomment-33805542) ;-)