Subject: bug#2756: move SCCS later in vc-handled-backends

From: Dan Nicolaescu <[email-masked]>
Date: Mon, 23 Mar 2009 10:25:21 -0700 (PDT)

SCCS should be moved after later in the vc-handled-backends list, after
the modern VCs.  

Opening any file costs a call to vc-sccs-registered
vc-sccs-search-project-dir (and whatever they call).

SCCS is not really popular nowadays, and that should be reflected on the
vc-handled-backends list.