[announce] BSDCan 2019 corrections

[NYC*BUG Announcements]

These are corrections sent by Dan L to the previous email:

> 
> 1 - The booking code for UOttawa residencies expires on 14 April (Sunday, tomorrow as I type this), not May as erroneously stated.
> 
> 2 - The closing social is $50, not $45.
> 
> In both cases, the website contained the correct information and my email was incorrect.
> 
> Sorry about that.  My apologies.
> 
> Keep in mind for the residences:
> 
> When booking accommodation at U90 (on campus), you may get told they are sold out. They are not. Be sure to check this:
>>
>> * you've used our booking code BSDCAN2019
>> * you're checking out on Sunday (the code only covers a certain period; if you want to stay longer, please make a separate booking, and pay for it when you arrive).