Display correct message for blockface restriction
Display correct message for blockface restriction

This fixes the case where trying to reserve an unavailable (surveyed)
blockface would display the message "This blockface has already been
reserved". While technically true, it's probably more accurate to
display the "This blockface is unavailable" message after it's been
surveyed.

kdeloach/nyc-trees,azavea/nyc-trees,maurizi/nyc-trees,maurizi/nyc-trees,maurizi/nyc-trees,kdeloach/nyc-trees,azavea/nyc-trees,azavea/nyc-trees,kdeloach/nyc-trees,maurizi/nyc-trees,kdeloach/nyc-trees,kdeloach/nyc-trees,azavea/nyc-trees,azavea/nyc-trees