Bug #619984: Remove "Gnumatic, Inc." from po/Makevars

Gnumatic Inc. does since a few years no longer exist.
So it makes no sense, to have it as copyright holder of new GnuCash
translations.

I got Linas OK for this change on IRC:
http://lists.gnucash.org/logs/2010/05/2010-05-28.html#T13:37:53 - #T16:12:23

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@19224 57a11ea4-9604-0410-9ed3-97b8803252fd

po/Makevars

@@ -18,7 +18,7 @@ XGETTEXT_OPTIONS = --keyword=_ --keyword=N_ --keyword=Q_
 # or entity, or to disclaim their copyright.  The empty string stands for
 # the public domain; in this case the translators are expected to disclaim
 # their copyright.
-COPYRIGHT_HOLDER = Gnumatic, Inc.
+COPYRIGHT_HOLDER =
 
 # This is the list of locale categories, beyond LC_MESSAGES, for which the
 # message catalogs shall be used.  It is usually empty.