BUG 1162 - ensure data for all path arguments in datastore.

Fixes
1) It is possible to specify path to data (including lists with
keys) via unexisting nodes and store payload data to this path.
Missing nodes in datastore are created before storing payload data.
2) InstanceIdentifier is now correctly created via
DataNormalizer.toNormalized()

Change-Id: If795a930015fef39a0029e808355d51357e2d5d5
Signed-off-by: Jozef Gloncak <jgloncak@cisco.com>
Merge "BUG 1162 - ensure data for all path arguments in datastore."