OO-3052: use the JSON token extractor for Facebook API

src/main/java/org/olat/login/oauth/spi/FacebookProvider.java

@@ -29,6 +29,8 @@ import org.olat.login.oauth.OAuthSPI;
 import org.olat.login.oauth.model.OAuthUser;
 import org.scribe.builder.api.Api;
 import org.scribe.builder.api.FacebookApi;
+import org.scribe.extractors.AccessTokenExtractor;
+import org.scribe.extractors.JsonTokenExtractor;
 import org.scribe.model.OAuthRequest;
 import org.scribe.model.Response;
 import org.scribe.model.Token;
@@ -68,7 +70,12 @@ public class FacebookProvider implements OAuthSPI {
 
 	@Override
 	public Api getScribeProvider() {
-		return new FacebookApi();
+		return new FacebookApi() {
+			@Override
+			public AccessTokenExtractor getAccessTokenExtractor() {
+				return new JsonTokenExtractor();
+			}
+		};
 	}
 
 	@Override