Add a getStatus() to check if cache is working

[remoe]

How can one check the cache is working? After calling this:

osg::ref_ptr<osgEarth::Cache> cache = CacheFactory::create( cacheOptions );
osgEarth::Registry::instance()->setDefaultCache( cache );

I have a case with the following error:

[osgEarth]* [RocksDBCache] Database problem...attempting to repair...
[osgEarth]* [RocksDBCache] Failed to open or create cache bin at C:\Users\user\AppData\Local\app\cache

I want to get this error case and clear the cache database.

http://forum.osgearth.org/check-if-cache-is-working-td7593113.html