Clear peer_addr if aborting XML POST changes the hostname

peer_addr needs to be reset if the host changes, or else we will connect
to the wrong host, and probably trigger a certificate mismatch.

References:

Commit d9aa66ba2d (Clear cached peer_addr where necessary)
http://lists.infradead.org/pipermail/openconnect-devel/2013-August/001136.html

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
JNI: Add generic userData storage

These can be used by the caller to store UI objects or other state
information.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>