Added new constructor for GraphServiceClient

To resolve 
#2354

Author: raghucha

src/main/java/com/microsoft/graph/serviceclient/GraphServiceClient.java

@@ -50,6 +50,16 @@ public GraphServiceClient(@Nonnull RequestAdapter requestAdapter) {
     public GraphServiceClient(@Nonnull AuthenticationProvider authenticationProvider) {
         this(new BaseGraphRequestAdapter(authenticationProvider, null, "v1.0" , getGraphClientOptions()));
     }
+    /**
+     * Instantiate the GraphServiceClient using an AuthenticationProvider, baseUrl and OkHttpClient.
+     * @param authenticationProvider The AuthenticationProvider for this GraphServiceClient.
+     * @param client The OkHttpClient for the GraphServiceClient.
+     * @param clouds The Clouds for the GraphServiceClient.
+     *
+     */
+    public GraphServiceClient(@Nonnull AuthenticationProvider authenticationProvider,@Nonnull OkHttpClient client, @Nonnull Clouds clouds) {
+        this(new BaseGraphRequestAdapter(authenticationProvider, clouds, "v1.0", getGraphClientOptions()));
+    }
     /**
      * Instantiate the GraphServiceClient using an AuthenticationProvider and OkHttpClient.
      * @param authenticationProvider The AuthenticationProvider for this GraphServiceClient.