temporarily raise acct creation throttle (NYC event)

http://metro.org/events/417/

Event ....... intro to WP @ metro.org
From ........ 2013-09-18 13:00 UTC
To .......... 2013-09-18 22:00 UTC
IPs ......... 64.80.165.148
Wikis ....... en.wikipedia
Threshold ... 50

Change-Id: I2bd69a00242c8858e6f5b2caf782b654c9cfabca
Merge "temporarily raise acct creation throttle (NYC event)"