documentation: update cvsimport description of "-r" for recent clone

the "--use-separate-remote" option no longer exists, having since
become the default for a clone.

Signed-off-by: Carlo Marcelo Arenas Belon <carenas@sajinet.com.pe>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-cvsimport.txt

@@ -62,7 +62,7 @@ OPTIONS
 -r <remote>::
 	The git remote to import this CVS repository into.
 	Moves all CVS branches into remotes/<remote>/<branch>
-	akin to the 'git-clone' "--use-separate-remote" option.
+	akin to the way 'git-clone' uses 'origin' by default.
 
 -o <branch-for-HEAD>::
 	When no remote is specified (via -r) the 'HEAD' branch