fix calendar events styling
fix calendar events styling

fixes COMMS-1044

Test Plan:
- create a calendar event on the calendar screen
- go view the calendar page in IE11
- notice it looks pretty

Change-Id: I33505a13482fe151f77f582b9550144b532dce2c
Reviewed-on: https://gerrit.instructure.com/146359
Reviewed-by: Landon Gilbert-Bland <60d9ff23682c863d36b48b4c32c5ce5f434d29c0@instructure.com>
Tested-by: Jenkins
QA-Review: Venk Natarajan <f9eab59b292314637a3c917fea4742741e36a19b@instructure.com>
Product-Review: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>

djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms