daemon: Really allow httpd.listenUrl to end with /

My earlier attempt to allow httpd.listenUrl to end with a / in
commit 4691f2f6cf was horribly broken.  Instead of clipping
the trailing slash off the path, we made the entire path exactly
"/" and thus bound the context to / and not /review like we wanted.

Change-Id: I667ce6f73043e79009d7836e061c6e71123cab82
Signed-off-by: Shawn O. Pearce <sop@google.com>

gerrit-pgm/src/main/java/com/google/gerrit/pgm/http/jetty/JettyServer.java

@@ -251,7 +251,7 @@ public class JettyServer {
         p = "/";
       }
       while (1 < p.length() && p.endsWith("/")) {
-        p = p.substring(p.length() - 1);
+        p = p.substring(0, p.length() - 1);
       }
       paths.add(p);
     }