Fix #1426 - Trim long usernames in public follower/following lists (#2993)

Fix #2221 - Catch OpenSSL exceptions when loading remote avatars/headers/attachments
Don't strip "rel" attribute from <a> tags when sanitizing (microformats)

app/models/concerns/account_avatar.rb

@@ -34,7 +34,7 @@ module AccountAvatar
 
       self.avatar              = URI.parse(parsed_url.to_s)
       self[:avatar_remote_url] = url
-    rescue OpenURI::HTTPError => e
+    rescue OpenURI::HTTPError, OpenSSL::SSL::SSLError, Paperclip::Errors::NotIdentifiedByImageMagickError => e
       Rails.logger.debug "Error fetching remote avatar: #{e}"
     end
   end

app/models/concerns/account_header.rb

@@ -34,7 +34,7 @@ module AccountHeader
 
       self.header              = URI.parse(parsed_url.to_s)
       self[:header_remote_url] = url
-    rescue OpenURI::HTTPError => e
+    rescue OpenURI::HTTPError, OpenSSL::SSL::SSLError, Paperclip::Errors::NotIdentifiedByImageMagickError => e
       Rails.logger.debug "Error fetching remote header: #{e}"
     end
   end