Remove outdated SOURCE reference to 
/sys/src/cmd/oventi/copy.c.

Reference: /n/sources/patch/applied/doc-man-1-venti-src
Date: Sat Dec 22 11:18:45 CET 2007
Signed-off-by: josh@utopian.net

--- /sys/man/1/venti	Sat Dec 22 11:18:31 2007
+++ /sys/man/1/venti	Sat Dec 22 11:18:28 2007
@@ -140,8 +140,6 @@
 It writes the new root score to standard output.
 .SH SOURCE
 .B /sys/src/cmd/venti
-.br
-.B /sys/src/cmd/oventi/copy.c
 .SH SEE ALSO
 .IR vac (1),
 .IR venti (2),