TXSocket::ProcesUnsolicitedMsg:
  - Fix desynchronization problem due to mutex being released too early;
TXSocketHandler::Notify, TXSlave::Init:
  - Optimize identification of owner TXSlave instance


git-svn-id: http://root.cern.ch/svn/root/trunk@14109 27541ba8-7e3a-0410-8455-c3a389f83636