cvsserver: Respond to the 'editors' and 'watchers' commands

These commands list users editing and watching locked files.  This trivial
implementation always returns an empty response, since git-cvsserver does not
implement file locking.

Without this, TkCVS hangs at startup, waiting forever for a response.

Signed-off-by: Damien Diederen <dash@foobox.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-cvsserver.perl

@@ -73,8 +73,8 @@ my $methods = {
     'status'          => \&req_status,
     'admin'           => \&req_CATCHALL,
     'history'         => \&req_CATCHALL,
-    'watchers'        => \&req_CATCHALL,
-    'editors'         => \&req_CATCHALL,
+    'watchers'        => \&req_EMPTY,
+    'editors'         => \&req_EMPTY,
     'annotate'        => \&req_annotate,
     'Global_option'   => \&req_Globaloption,
     #'annotate'        => \&req_CATCHALL,
@@ -199,6 +199,11 @@ sub req_CATCHALL
     $log->warn("Unhandled command : req_$cmd : $data");
 }
 
+# This method invariably succeeds with an empty response.
+sub req_EMPTY
+{
+    print "ok\n";
+}
 
 # Root pathname \n
 #     Response expected: no. Tell the server which CVSROOT to use. Note that