GUAC-586: Associate AuthenticationProvider directly with UserContext.

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-postgresql/src/main/java/org/glyptodon/guacamole/auth/postgresql/PostgreSQLAuthenticationProvider.java

@@ -185,7 +185,8 @@ public class PostgreSQLAuthenticationProvider implements AuthenticationProvider
             new PostgreSQLAuthenticationProviderModule(environment),
 
             // Configure JDBC authentication core
-            new JDBCAuthenticationProviderModule(environment, getTunnelService(environment))
+            new JDBCAuthenticationProviderModule(this, environment,
+                    getTunnelService(environment))
 
         );