Revert "devapp: remove trailing slash from /owners handler"

This reverts commit 768b50a198051f8a13b71e076ebe35c34f190dcb (CL 171360)

Reason for revert: breaks existing gopherbot client

Change-Id: I553f11ce21475ac1f073462a739acc9b2ee79ed6
Reviewed-on: https://go-review.googlesource.com/c/build/+/171460
Reviewed-by: Bryan C. Mills <bcmills@google.com>
diff --git a/devapp/server.go b/devapp/server.go
index 5d8e433..cb19cd0 100644
--- a/devapp/server.go
+++ b/devapp/server.go
@@ -65,7 +65,7 @@
 	s.mux.HandleFunc("/release", s.withTemplate("/release.tmpl", s.handleRelease))
 	s.mux.HandleFunc("/reviews", s.withTemplate("/reviews.tmpl", s.handleReviews))
 	s.mux.HandleFunc("/dir/", handleDirRedirect)
-	s.mux.HandleFunc("/owners", owners.Handler)
+	s.mux.HandleFunc("/owners/", owners.Handler)
 	for _, p := range []string{"/imfeelinghelpful", "/imfeelinglucky"} {
 		s.mux.HandleFunc(p, s.handleRandomHelpWantedIssue)
 	}