- 'set terminal history off' or '... limit 0' has an incorrect
terminal condition and tries to vec_delete one-too-many times
causing a crash.
- Changing >= to > fixes this.
- In any case, a single vec_delete is more efficient, so do that
instead.
Change-Id: Ia0db63b6c5c7891d75b302e793b4e4985dd86ebb
Signed-off-by: Chris Luke <chrisy@flirble.org>