CLC-4178 - Update gems - font-awesome-rails

https://jira.ets.berkeley.edu/jira/browse/CLC-4178
https://github.com/FortAwesome/Font-Awesome/issues?milestone=12&q=is%3Aclosed
Merge pull request #2865 from christianv/CLC-4178

CLC-4178 - Update gems - font-awesome-rails