chat/unrealircd: update distinfo.

The tarball was silently updated without a release. After diffing this
against the git tag, the updated tarball seems to change some if statements
from if (x = y) to if (x == y)...

https://github.com/unrealircd/unrealircd/commit/766055d5c0399fa55d03ac6ab33804dc084e2547

The bug fixed by this change is apparently not exploitable.

(nia)