Fix missing default value

Author: pedrodim

src/style.scss

@@ -67,7 +67,7 @@ $picker-color: $_coolGrey !default;
 $picker-color-hover: $_darkGrey !default;
 
 $picker-background: $_white !default;
-$picker-background-hover: !default;
+$picker-background-hover: $_paleGrey !default;
 
 $picker-border-radius: 2px !default;
 $picker-border-color: #d9dee3 !default;