libcontainer/sync: Drop procConsole transaction from comments
These were added in 244c9fc4 (*: console rewrite, 2016-06-04,
alongside procConsole and the associated handling.  procConsole and
that handling were removed in (Add separate console socket,
2017-03-02, but 00a0ecf5 missed this comment.
@@ -19,11 +19,6 @@ type syncType string
// procHooks --> [run hooks]
// <-- procResume
//
-// procConsole -->
-// <-- procConsoleReq
-// [send(fd)] --> [recv(fd)]
-// <-- procConsoleAck
-//
// procReady --> [final setup]
// <-- procRun
const (
