bug#5428: vc-annotate for Bzr does not show the date

[Dan Nicolaescu]

The subject says it all, dates are not displayed by vc-annotate for bzr.

This is very bad, the date is very useful information.

It is available as a tooltip, but one cannot search for the information
in the tooltip.

What is worse is that this is inconsistent with what vc-annotate does
for all other backends, where the date is shown just fine.

`vc-bzr-annotate-command' goes through a lot of effort to reformat the
vc-annotate buffer with the end result of just hiding the date, and
changing the format of "author". 

The date is in a very compact format YYYYMMDD, so it does not take much
screen space.
If that is a problem we have the
vc-annotate-toggle-annotation-visibility command to hide all the extra
information.

vc-bzr-annotate-command should just limit itself to run the "bzr annotate"
command.  Just vc-bzr-annotate-time needs a minor adjustment to make
everything work.