":quit" exits outer "stack ghci" when running "stack ghci" within

Repro:

1) `stack ghci --build-only-dependencies stack:stack stack:lib` (in stack repo)
2) `:set args ghci --build-only-dependencies`
3) `main` (starts up another ghci session)
4) `:quit`

Actual: Exits all the way back to the shell

Expected: Back in the outer ghci session
