jsterm-911456: Adding missing this in error case
jsterm-911456: Adding missing this in error case

The code that handles cases when we force execute invalid code was
missing a ".bind(this)". This was not a problem for GCLI previously
because we didn't allow force execution of invalid code.

Signed-off-by: Joe Walker <7a17872fbb32c7d760c9a16ee3076daead11efcf@mozilla.com>

mozilla/gcli,joewalker/gcli,mozilla/gcli,joewalker/gcli,mozilla/gcli