Fix BIRD show protocols partitioning

Fix BirdShowProtocolsCommand and parseBirdShowProtocols not to duplicate
partitioning of the result (for the display as a table). Before this patch
it didn't worked because parseBirdShowProtocols reduced results to i.e.
[100..200] and later decorateResult in BirdShowProtocols reduced the
previously reduced result of length 100 to [100..200] which is empty.