fix minor crash with term-init-string prefs

[vapier]

The storage call here will return an empty object when the key isn't found which causes this code to pass undefined down to the terminal print layers (which then crashes). It doesn't affect the running of the app because this is a callback func in its own execution scope, but it does clutter up the console log.

[vapier]

ah looks like someone already discovered & proposed a fix at #161. you can decide which form you like better ;).

[vapier]

that one was merged, so no need for this anymore