Interrupt after first tabbing into a menu select clears prompt

[Philip Sequeira <phsequei@xxxxxxxxx>]

This is a regression, been happening for a while but I never got
around to tracking it down.

From zsh -f:
zstyle ':completion:*' menu select=0
autoload -Uz compinit
compinit
ls<Tab><Tab>^C

And the prompt disappears. As far as I can tell, it only happens if
you interrupt right after tabbing into the list, without doing
anything else. If you go to another entry, or even back to the first
one, before hitting ^C, it won't disappear.

Bisected to 32f5d3d8c16b4f3a11fa39c0ee378d72336ba853. Removing the if
(!errflag) added by that commit fixes my problem, but I guess you'll
want to add another check or something instead if you still think that
propagating an error should usually not redraw the line.