IDE-1561 liferay maven project with custom jsps validation

This wont work the way you are thinking... once you have both instance and default prefs you need to chain them like this

```
final boolean disableCustomJspValidation =
                        LiferayMavenCore.getPrefs().getBoolean(
                            LiferayMavenCore.PREF_DISABLE_CUSTOM_JSP_VALIDATION,
                            LiferayMavenCore.getDefaultPrefs().getBoolean(
                                LiferayMavenCore.PREF_DISABLE_CUSTOM_JSP_VALIDATION, true ) );
```