fix possible problem with --link-pois-to-ways option

A boolean field was not properly initialised. As a result,
one or more route restrictions were not written when 
a way with a barrier at the start or end point is connected to
multiple ways with different access rights, so that the barrier
was ignored in these cases. 


git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@3206 25d90789-57f7-4ee0-8453-03a3dfeeeb22