*_link roads are now rendered as black

[skorasaurus]

While investigating #271 today, my local instance was displaying all highways tagged as *_link (including primary_link, secondary_link) as black.

This was introduced by the most recent commit

I tested it out on the older commit and *_link highways were rendered as intended.

Here's what Dominican republic looks like:

I've viewed several of those roads and the only common tag among all of them is the highway=*_link tag.

[yohanboniface]

Good catch! I've reverted. We don't really care about rendering non standard xxx_link at the end.