@Override
            public void vCardDeleted(String username, Element vCard) {
                // Since the vCard could be delated by the provider, remove it to the cache.
                vcardCache.remove(username);
            }
Returns the currently-installed VCardProvider. <b>Warning:</b> in virtually all
cases the vcard provider should not be used directly. Instead, the appropriate
methods in VCardManager should be called. Direct access to the vcard provider is
only provided for special-case logic.

@return the current VCardProvider.
xmppserver/src/main/java/org/jivesoftware/openfire/vcard/VCardManager.java