Minor consistency fixes to sidebar & header

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

app/assets/stylesheets/framework/header.scss

@@ -25,7 +25,7 @@ header {
     padding: 0 16px;
     z-index: 100;
     margin-bottom: 0;
-    min-height: $header-height;
+    height: $header-height;
     background-color: $background-color;
     border: none;
     border-bottom: 1px solid $border-color;

app/assets/stylesheets/framework/sidebar.scss

@@ -98,7 +98,7 @@
   }
 
   .sidebar-user {
-    padding: 9px 22px;
+    padding: 7px 22px;
     position: fixed;
     bottom: 40px;
     width: $sidebar_width;