... (and setting mbDowning to indicate an error returned from accept() is due to
termination) instead of setting up an extra pipe connection to send an
"InternalIPC::TerminateThread" message (which allegedly caused deadlocks, see
<https://gerrit.libreoffice.org/#/c/1311/> "Change Idf933915: office ipc: use
timeout pipe feature when connecting to self").

Change-Id: Id302ca13112fc409685e7665b38f1030704a0ccf