Bug 1106238 - about:home search icon has a solid background, should be transparent. r=felipe

--HG--
extra : rebase_source : 4683852f44862f9bd3dee83669aeb9ebb4fe41dd

browser/base/content/abouthome/aboutHome.css

@@ -81,16 +81,14 @@ a {
   -moz-margin-end: 5px;
   height: 38px;
   width: 38px;
-  background-image: url("chrome://browser/skin/magnifier.png");
+  background: url("chrome://browser/skin/magnifier.png") center center no-repeat;
   background-size: 26px;
-  background-position: center center;
-  background-repeat: no-repeat;
 }
 
 #searchIcon[active],
 #searchIcon:hover {
   background-color: #e9e9e9;
-  border: 1px solid rgb(226, 227, 229);
+  border-color: rgb(226, 227, 229);
   border-radius: 2.5px;
 }