Use transaction chaining

Topology providers usually expect the state to be present in the data
store when they update it. Transaction chaining adds the ordering
guarantee, which is needed to prevent false positives uncovered by the
recent speedup of the datastore.

Change-Id: Ie17a83303485d592640d094d53eff695a3c05bb1
Signed-off-by: Robert Varga <rovarga@cisco.com>