BUG-429: Turn putOperationalData() in replace operations

It turns out that putOperationalData is really a merge, not a replace.
Force it to a replace by issuing an explicit remove. This depends on
https://git.opendaylight.org/gerrit/#/c/5106/ to work as designed.

Change-Id: Ic7106c51c7226d9c06aa78df56efb9adc834b74b
Signed-off-by: Robert Varga <rovarga@cisco.com>