files: use consistent gravatar rendering using email only.

rhodecode/templates/files/files_tree_header.mako

@@ -1,46 +1,46 b''
 <%namespace name="base" file="/base/base.mako"/>
 <%namespace name="file_base" file="/files/base.mako"/>
 
 <div class="summary">
   <div class="fieldset">
     <div class="left-content">
 
       <div class="left-content-avatar">
-        ${base.gravatar(c.commit.author, 30)}
+        ${base.gravatar(c.commit.author_email, 30)}
       </div>
 
       <div class="left-content-message">
         <div class="fieldset collapsable-content no-hide" data-toggle="summary-details">
           <div class="commit truncate-wrap">${h.urlify_commit_message(h.chop_at_smart(c.commit.message, '\n', suffix_if_chopped='...'), c.repo_name)}</div>
         </div>
 
         <div class="fieldset collapsable-content" data-toggle="summary-details">
           <div class="commit">${h.urlify_commit_message(c.commit.message,c.repo_name)}</div>
         </div>
 
         <div class="clear-fix">
           <span class="commit-author">${h.link_to_user(c.commit.author)}</span><span class="commit-date"> - ${h.age_component(c.commit.date)}</span>
         </div>
       </div>
     </div>
 
     <div class="right-content">
       <div class="tags commit-info">
         <code>
             <a href="${h.route_path('repo_commit',repo_name=c.repo_name,commit_id=c.commit.raw_id)}">${h.show_id(c.commit)}</a>
         </code>
 
         ${file_base.refs(c.commit)}
       </div>
     </div>
 
     <div class="clear-fix"></div>
 
     <div  class="btn-collapse" data-toggle="summary-details">
         ${_('Show More')}
     </div>
   </div>
 </div>
 <script>
   collapsableContent();
 </script>