Delete all cache entries.
boolean TRUE if the cache entries were successfully deleted, FALSE otherwise.
public function deleteAll() {
$namespaceCacheKey = $this
->getNamespaceCacheKey();
$namespaceVersion = $this
->getNamespaceVersion() + 1;
$this->namespaceVersion = $namespaceVersion;
return $this
->doSave($namespaceCacheKey, $namespaceVersion);
}