cvsserver: use whole CVS rev number in-process; don't strip "1." prefix

Keep track of the whole CVS revision number in-process.  This will
clarify code when we start handling non-linear revision numbers later.

There is one externally visible change: conflict markers after
an update will now include the full CVS revision number,
including the "1." prefix.  It used to leave off the prefix.

Other than the conflict marker, this change doesn't effect
external functionality.  No new features, and the DB schema
is unchanged such that it continues to store just
the stripped rev numbers (without prefix).

Signed-off-by: Matthew Ogilvie <mmogilvi_git@miniinfo.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>