Fix Find/Replace-o; good catch, @FagnerMartinsBrack!

Problem introduced in 6b23a66c

less/popovers.less

@@ -13,8 +13,8 @@
   padding: 1px;
   text-align: left; // Reset given new insertion method
   background-color: @popover-bg;
-  -webkit-bg-clip: padding-box;
-     -moz-bg-clip: padding;
+  -webkit-background-clip: padding-box;
+     -moz-background-clip: padding;
   background-clip: padding-box;
   border: 1px solid @popover-fallback-border-color;
   border: 1px solid @popover-border-color;