Align vertically loading icon and status message

As both elements are inline/inline-block and belong to the same line
they can be aligned vertically using "vertical-align: middle".

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>

apps/theming/css/settings-admin.css

@@ -49,10 +49,6 @@ form.uploadButton {
     visibility: visible;
 }
 
-#theming .icon-loading-small:after {
-    margin: -10px 0 0 -10px;
-}
-
 #theming label span {
     display: inline-block;
     min-width: 120px;
@@ -74,11 +70,15 @@ form.uploadButton {
 
 }
 #theming_settings_loading.icon-loading-small {
-    float: left;
-    padding: 0;
+    display: inline-block;
+    vertical-align: middle;
     margin-right: 10px;
 }
 
+#theming_settings_msg {
+    vertical-align: middle;
+}
+
 #theming-preview-logo {
     cursor: pointer;
 }