fix infinite loop on client disconnected socket

--HG--
branch : nmdc-ircfrontend

server.go

@@ -101,8 +101,12 @@ func (s *Server) RunWorker() {
 			if err == io.EOF {
 				break // abandon thread
 			}
+
+			// If this was a /timeout/, send a KA and continue.
+
+			// But otherwise, it was a real error (e.g. unexpected disconnect)
 			s.verboseln(err.Error())
-			continue
+			break // abandon
 		}
 
 		rawLines := buf[:ln]