Also do callback on the failing function

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

core/js/jquery.avatar.js

@@ -129,6 +129,10 @@
 				setAvatarForUnknownUser($div);
 				$div.removeClass('icon-loading');
 			}
+
+			if(typeof callback === 'function') {
+				callback();
+			}
 		};
 
 		$div.addClass('icon-loading');