Fix double border in MR discussion

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/assets/stylesheets/framework/timeline.scss

@@ -10,8 +10,7 @@
     margin-left: -$gl-padding;
     margin-right: -$gl-padding;
     color: $gl-gray;
-    border-bottom: 1px solid #ECEEF1;
-    border-right: 1px solid #ECEEF1;
+    border-bottom: 1px solid $border-white-light;
 
     &:target {
       background: $hover;

app/assets/stylesheets/pages/issuable.scss

@@ -51,7 +51,7 @@
   }
 
   section {
-    border-right: 1px solid #ECEEF1;
+    border-right: 1px solid $border-white-light;
 
     > .tab-content {
       margin-right: 1px;

app/assets/stylesheets/pages/issues.scss

@@ -149,3 +149,10 @@ form.edit-issue {
 .issue-form .select2-container {
   width: 250px !important;
 }
+
+
+.issue-discussion {
+  .common-note-form {
+    border-right: 1px solid $border-white-light;
+  }
+}

app/assets/stylesheets/pages/note_form.scss

@@ -79,7 +79,6 @@
   padding: $gl-padding;
   margin-left: -$gl-padding;
   margin-right: -$gl-padding;
-  border-right: 1px solid $border-color;
   border-top: 1px solid $border-color;
   margin-bottom: -$gl-padding;
 }