spice-html5: spice_auto.html - actually use ?path when given

Right now, `spice_auto.html` reads the path from query string .. and
never actually does anything with it. This should make
`spice_auth.html` respect a path parametr when given.

spice_auto.html

@@ -128,6 +128,10 @@
 
                 uri = scheme + host + ":" + port;
 
+                if (path) {
+                  uri += path[0] == '/' ? path : ('/' + path);
+                }
+
                 try
                 {
                     sc = new SpiceMainConn({uri: uri, screen_id: "spice-screen", dump_id: "debug-div",