[PATCH 0 of 2] convert: add an option to inhibit hg sink tag updates

[Giorgos Keramidas]

In a few of the conversion scripts I am using I pull changes only
from one branch of the source repository, and want to keep only
the original source changesets without .hgtags updates.  What I
was using until now was something like the following Git source
sample:

  hg convert -r origin/master /work/git/emacs /hg/emacs/master
  cd /hg/emacs/master
  hg update --clean tip
  hg strip tip

The new option added here makes the (somewhat dangerous) strip
part redundant, by adding a convert.hg.tags='False' command-line
option:

  hg convert --config 'convert.hg.tags=False' -r origin/master \
      /work/git/emacs /hg/emacs/master

The effect of the new option is that puttags() does nothing, and
'.hgtags' is explicitly stripped from changeset files as they are
pushed to the sink.

The default is 'convert.hg.tags=True', so the usual behavior of
convert is kept unmodified.