Fix linters

app/views/proposals/_speaker_info.haml

@@ -1,13 +1,13 @@
 .speakerinfo
   .row
     .col-md-4
-      = image_tag speaker.profile_picture(:size => 120), class: 'img-responsive img-rounded'
+      = image_tag speaker.profile_picture(size: 120), class: 'img-responsive img-rounded'
     .col-md-8
       %h4
         = link_to speaker.name, user_path(speaker.id)
         %br
         - if speaker.email_public?
-          = mail_to "#{ speaker.email }" do
+          = mail_to speaker.email.to_s do
             %i.fa.fa-envelope-o.fa-2x
       - if speaker.affiliation?
         .text-muted