Fix release build TLS connection bug!
Created by: LNJ2
The problem was that the ServiceDiscoveryManager also is a gloox::ConnectionHandler, but isn't return anything upon a handleTls call, so this resulted in a true return in gcc (<= 7) in debug mode. gcc (<= 7) in release mode and gcc-8 and clang in debug mode made it just fail. g++-8 and clang in release mode just gave a segfault.