Don't fail badly on setting VT screen size. Refs #9742.

We still need to be able to set the screen size within a multiprocessing
process.
Only try to set the terminal size if parent is a TTY
Catch all VT spawnign errors.

Fix the logging call and try to catch any errors occurring while
spawning the VT.
Make PyLint happier.
Merge pull request #9765 from s0undt3ch/2014.1

VT fixes