oc-sogo: try/catch to guard only the actual impelementation rather than *everything*

Signed-off-by: Kamen Mazdrashki <kmazdrashki@zentyal.com>
oc-sogo: Clean up AutoRelease pool and unregister threads in Catch handler

Most of the time we have "not yet implemented" kind of exceptions,
so it is better to clean up allocated resources

Signed-off-by: Kamen Mazdrashki <kmazdrashki@zentyal.com>