revert back and use an Servlet listener to init the indexer logic which
is heavy weight and needs a fully started container. Remove
PostConstruct and PreDestroy and call them explicitly from context
listener. Run them as RequestScope to have DB access as well.
add a reason why to change into Request Scope
remove unused import
Interceptor method initAvailableInstances defined on class
org.backmeup.index.core.elasticsearch.SearchInstances is not defined
according to the specification. It should not throw a checked exception.
Revert "add a reason why to change into Request Scope"

This reverts commit cc658f4530146f4f14bfcea2d5a8cf76b280ef25.
remove unused import
remove unused local variable
fixed: do not assign parameter