NormalizedNodeAggregator should also report empty
DataTree root is always present as of now, which means that even if we
pretend there is no result, the result of aggregation is non-empty.
Fix NormalizedNodeAggregator to check whether there was any operation
applied before running actual transaction.
JIRA: CONTROLLER-2038
Change-Id: Ie7e4625ad2377483d0623d96234bcc77fbba033d
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>
(cherry picked from commit
1d5ca4009be6c61d7b61989799037ad8f1ab7a75)