Adjust provisioning to allow for use with RabbitMQ

Slight changes to the provisioning to allow login to RabbitMQ MQTT broker.
With RabbitMQ the username and password must be submitted as part of the URL:
`mqtt://user:password@broker.domain`.

Signed-off-by: Winford <winford@object.stream>

priv/provision.html

@@ -370,7 +370,6 @@ <h2>Device</h2>
             type="text"
             name="gateway_user"
             placeholder="Enter MQTT username"
-            required
             />
         </div>
 
@@ -380,7 +379,6 @@ <h2>Device</h2>
             type="password"
             name="gateway_pass"
             placeholder="Enter MQTT password"
-            required
             />
         </div>
 

src/c3card_provision.erl

@@ -86,8 +86,8 @@ handle_req("POST", [], Conn) ->
     Pass = proplists:get_value("pass", Params),
     EnableMQTT = proplists:get_value("gateway_enabled", Params, "off"),
     Gateway = proplists:get_value("gateway", Params),
-    User = proplists:get_value("gateway_user", Params),
-    Password = proplists:get_value("gateway_pass", Params),
+    User = proplists:get_value("gateway_user", Params, ""),
+    Password = proplists:get_value("gateway_pass", Params, ""),
     DeviceName = proplists:get_value("device_name", Params),
 
     ok = save_config(