Remove avatar from comment form

Author: takezoe

src/main/twirl/gitbucket/gist/commentform.scala.html

@@ -3,7 +3,6 @@
 @if(context.loginAccount.isDefined){
   <hr/><br/>
   <form method="POST" validate="true" action="@context.path/gist/@gist.userName/@gist.repositoryName/_comment">
-    <div class="issue-avatar-image">@helpers.avatar(context.loginAccount.get.userName, 48)</div>
     <div class="panel panel-default issue-comment-box">
       <div class="panel-body">
         @gitbucket.gist.html.commentpreview(