Bad bit.ly link created

[nchernia]

To reproduce, go here:

http://bit.ly/2PRj95e

To the map with only 2 tracks, add a third. I added ENCODE GM12878 H3K27ac.

Click "Share". The link created is this: http://bit.ly/2V0V53J

It doesn't work; it resolves to https://aidenlab.org/juicebox/?juiceboxURL=undefined