Bug 40012: Fix about:tor not loading some images in 82

Changed their URLs to relative ones.

chrome/skin/aboutTor.css

@@ -195,7 +195,7 @@ body:not([showmanual]) .showForManual {
   height: auto;
   width: 50px;
   display: inline-block;
-  background: url('chrome://torbutton/skin/searchLogo.png') no-repeat center center;
+  background: url('searchLogo.png') no-repeat center center;
   background-size: 30px 30px;
 }
 
@@ -203,7 +203,7 @@ body:not([showmanual]) .showForManual {
   height: auto;
   width: 36px;
   border: 0;
-  background: url('chrome://torbutton/skin/forwardArrow.png') no-repeat center center;
+  background: url('forwardArrow.png') no-repeat center center;
   background-size: 16px 14px;
   cursor: pointer;
 }