Changed close() to use clearPassword() (#155).

Author: gmessner

src/main/java/org/gitlab4j/api/utils/Oauth2LoginStreamingOutput.java

@@ -57,7 +57,7 @@ public void clearPassword() {
 
     @Override
     public void close() {
-        password.clear();
+        clearPassword();
     }
 
     @Override