bug#17945: 24.4.50; vc-git-annotate-command is too slow

[Dmitry Gutov]

On 02/25/2015 08:06 PM, Óscar Fuentes wrote:

> vc-switches does check `vc-annotate-switches' (as it checks
> vc-OP-switches for any other OP and BACKEND), so we are hiding
> information from the user.

But there's no such user option. And if a variable with that name is 
created, well, the user stepped on something nobody asked them too.

> The whole problem consists on a generic approach (vc-OP-switches) that
> doesn't play nice for some (all?) OPs. So we either get rid of
> `vc-OP-switches' entirely or warn the user about its pitfalls.

I think in this case we can just as well avoid using `vc-switches' and 
reference `vc-git-annotate-switches' directly.

> (Is there an OP where `vc-OP-switches' works well across more than two
> supported backends?)

vc-diff-switches works pretty well.

The rest of -switches variables, though, look similarly suspicious to 
me. That's vc-checkin-switches, vc-checkout-switches and 
vc-register-switches.