Remove the author name from issue notes emails

Rationale: the author name is now displayed in the email "From" field;
this information is no longer needed.

app/views/notify/_note_message.html.haml

@@ -1,6 +1,2 @@
-%p
-  %strong #{@note.author_name}
-  wrote:
-
 %cite{style: 'color: #666'}
   = markdown(@note.note)

spec/mailers/notify_spec.rb

@@ -353,10 +353,6 @@ describe Notify do
           should deliver_to recipient.email
         end
 
-        it 'contains the name of the note\'s author' do
-          should have_body_text /#{note_author.name}/
-        end
-
         it 'contains the message from the note' do
           should have_body_text /#{note.note}/
         end