[OE-core] [dylan]devshell: broken

[Andre]

bitbake -c devshell seems to have stopped working (tested with xterm
and mate-terminal) in dylan since this commit:

  a749f06 terminal: Run command using a wrapper script

It looks like the run.do_devshell.<PID> script is generated but then
fails to run when passed to a terminal.

A possible clue is that after manually editing the do_devshell script
to replace:

  do_terminal() {
  exec pseudo /bin/bash
  }

with:

  do_terminal() {
  exec /bin/bash
  }

the script runs OK when passed to a terminal manually, such as:

  $ xterm -e tmp/work/.../temp/run.do_terminal.25789