Metrics: Expected range contains negative numbers.

When one looks at the number of direct users in Taiwan, and one enables "Show possible censorship events if available" with "On: both points and expected range", the range displays negative numbers:

https://metrics.torproject.org/userstats-relay-country.html?start=2011-11-02&end=2016-11-10&country=tw&events=on

This should be fixed to only contain positive numbers.

Trac:
Username: madystar