Currently we support strict/non-strict label in PostReview,
which is controlled by the 'strictLabels' option.
For strict labels, we require all labels to be within the
user's granted range. Attempting to vote a label value not
granted will fail the entire operation. For non-strict labels,
we squashes the proposed value to the nearest granted value
and the operation will be executed.
This change removes the support for non-strict labels.
Change-Id: Icb9dfafea567e1e9c469811e830e3519b865700f
9ff64a60c5