[CUPS] Adjust the "Browse" button position a little bit.

BUG=725147
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2896063002
Cr-Commit-Position: refs/heads/master@{#474013}

chrome/browser/resources/settings/printing_page/cups_add_printer_dialog.html

@@ -269,6 +269,7 @@
       }
 
       #browseButton {
+        -webkit-margin-start: 5px;
         color: black;
         font-size: inherit;
       }