make affix smoother

Author: ckj

src/sentry/static/sentry/less/sentry.less

@@ -809,7 +809,7 @@ a.icon-share {
 
     .stream-actions-cell {
       box-shadow: none;
-      border: 0;
+      border-color: transparent;
     }
   }
 }

src/sentry/templates/sentry/groups/group_list.html

@@ -11,7 +11,7 @@
 {% block content %}
     {% querystring from request without sort as sort_querystring %}
     {% querystring from request without since as since_querystring %}
-    <div class="group-header-container" data-spy="affix" data-offset-top="200">
+    <div class="group-header-container" data-spy="affix" data-offset-top="195">
     <div class="container">
     <div class="group-header">
       <div class="stream-actions">