appman-controller -ioe doesn't work with containers

Connecting std::err und std::out with appman-controller by adding the -ioe doesn't work when running the app in a container.

Testing it we just received a return value of "2" (or "-2", don't quite remember) and the app wouldn't start.

Using this without a container works fine.

Btw, the -ioe argument is not mentioned in the usage text which is printed out when running with --help.