Make "don't build ctags image" check less agressive
Created by: mrnugget
Turns out my previous PR #13218 was a regression.
We set CTAGS_COMMAND
to cmd/symbols/universal-ctags-dev
in
./dev/start.sh
by default. That means if you've never built the Docker
image, we'd never build it with the old code.
This changes the fix so that we only don't build the image if you have a custom executable specified.
Thanks to @macraig for uncovering this!