Update JavaHL's tunnel callback API to match changes in the RA API.

[in subversion/bindings/javahl]
* src/org/apache/subversion/javahl/callback/TunnelAgent.java
  (TunnelAgent.CloseTunnelCallback): New nested interface.
  (TunnelAgent.openTunnel): Return an optional close-tunnel object.
  (TunnelAgent.closeTunnel): Removed, obsolete.

* native/JNIUtil.h (SVN_JNI_CATCH_VOID): New macro.
* native/OperationContext.h (inner_closeTunnel): Remove.
* native/OperationContext.cpp (OperationContext::TunnelContext):
   Revert r1562425; remove the tunnel_name, user, host and port members.
   Add jclosecb member, a reference to the close-tunnel interface.
  (OperationContext::openTunnel): Update TunnelContext construction,
   the call to the Java openTunnel implementation, and populate the
   TunnelContext::jclosecb.
  (OperationContext::closeTunnel):
   Merged into OperationContext::inner_closeTunnel.
   Update propagation to Java callback to the new API.

* tests/org/apache/subversion/javahl/BasicTests.java
  (BasicTests.Tunnel): Update to the new TunnelAgent API.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1563078 13f79535-47bb-0310-9956-ffa450edef68