Bug 833645: Add proxy for en-US bedrock firstrun page.

etc/httpd/global.conf

@@ -159,3 +159,6 @@ RewriteRule ^/(\w{2,3}(?:-\w{2}(?:-mac)?)?/)?firefox/partners(.*)$ /b/$1firefox/
 
 # bug 831810
 RewriteRule ^/(\w{2,3}(?:-\w{2}(?:-mac)?)?/)?mwc/?$ /$1firefox/partners/ [L,R=301]
+
+# bug 833645
+RewriteRule ^/en-US/firefox(/(?:\d+\.\d+\.?(?:\d+)?\.?(?:\d+)?(?:[a|b]?)(?:\d*)(?:pre)?(?:\d)?))?/firstrun(/?)$ /b/en-US/firefox$1/firstrun$2 [PT]