Memory Leak in the Rest server

The Netty rest server upon each connection will install the Http20RequestHandler that in turn creates a new instance of CacheOperations and RestCacheManager objects.

The RestCacheManager on every connection, among other things, will create hashmaps to keep cache instances, and will try to register every time a new RestSourceMigrator which gets accumulated in the RollingUpgradeManager.

Those objects should be shared across all channels so that they can efficiently cache resources and avoid creating lots of garbage.