mapnik2: revision for recent icu4c update
mapnik2: revision for recent icu4c update

Closes #1079.

Closes #1080.

Signed-off-by: Dominyk Tiller <53e438f55903875d07efdd98a8aaf887e7208dd3@gmail.com>

heuermh/homebrew-versions,coeligena/homebrew-verscustomized,jimhe/homebrew-versions,DomT4/homebrew-versions,Ashton-W/homebrew-versions,UniqMartin/homebrew-versions