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

[Dmitry Gutov]

On 02/24/2015 07:57 PM, Glenn Morris wrote:

> except vc-annotate-switches does not exist and would also
> need to be added.

I think this is only justified if we expect different backends' annotate 
command to receive the same options.

So far, only '-w' looks a likely candidate, albeit its descriptions are 
a bit different between Git and Hg. And it's not in e.g. Bzr.

What if the user sets `vc-annotate-switches' to '-w', and then calls 
`vc-annotate' in a Bazaar repository, where it'll obviously lead to failure?

> And for consistency, presumably all backends should
> get the same treatment. Thanks.

Probably. But I'd rather the present patch gets installed without too 
much delay.