Updated nginx to 1.9.0.

This also updates the container image to Debian 8 Jessie.

library/nginx

@@ -1,6 +1,6 @@
 # maintainer: NGINX Docker Maintainers <[email protected]> (@nginxinc)
 
-latest: git://github.com/nginxinc/docker-nginx@abd253dde5d627b151cd737ce953d6d01e6fdf4c
-1: git://github.com/nginxinc/docker-nginx@abd253dde5d627b151cd737ce953d6d01e6fdf4c
-1.7: git://github.com/nginxinc/docker-nginx@abd253dde5d627b151cd737ce953d6d01e6fdf4c
-1.7.12: git://github.com/nginxinc/docker-nginx@abd253dde5d627b151cd737ce953d6d01e6fdf4c
+latest: git://github.com/nginxinc/docker-nginx@2d9dbca5d2a916b90227863bb8f1a6458e5083c5
+1: git://github.com/nginxinc/docker-nginx@2d9dbca5d2a916b90227863bb8f1a6458e5083c5
+1.9: git://github.com/nginxinc/docker-nginx@2d9dbca5d2a916b90227863bb8f1a6458e5083c5
+1.9.0: git://github.com/nginxinc/docker-nginx@2d9dbca5d2a916b90227863bb8f1a6458e5083c5