Increase account creation throttle on enwiki for Cochrane colloquium.

Relavent ips: 182.72.146.126, 61.12.40.10, 123.63.128.158, 202.65.142.14

This is appearently happening right now, and thus a matter of some
urgency :s.

Bug: 71090
Change-Id: I7bb42b49a3c52aa536b53db0a9857a6e2cea6be8