Move more redirect rules to nginx config file. Reduce load.

nginx.common.conf

+    ## Several subdirectories map cleanly to gcloud bucket.
+    rewrite ^/(civicrm-l10n-core|civix|cv|git-scan|civistrings|amp|joomlatools-console)/(.*)$ https://storage.googleapis.com/civicrm/$1/$2 last;
+
+    location / {
+        try_files $uri @rewrite;
+    }
+
+    location @rewrite {
+        ## Primary tarballs in the root don't map cleanly.
+        rewrite ^/(.*)$ /index.php?q=$1;
+    }

nginx.example.txt

@@ -5,14 +5,7 @@ server {
     listen       [::]:80;
 
     root /var/www/example.com/web;
-
-    location / {
-        try_files $uri @rewrite;
-    }
-
-    location @rewrite {
-        rewrite ^/(.*)$ /index.php?q=$1;
-    }
+    include /var/www/example.com/nginx.common.conf;
 
     location ~ \.php$ {
         fastcgi_split_path_info ^(.+\.php)(/.+)$;

web/index.php

@@ -12,9 +12,6 @@ function pick_url($path) {
       return "$base/civicrm-stable/$version/$path";
     }
   }
-  if (preg_match(';^(civicrm-l10n-core|civix|cv|git-scan|civistrings|amp|joomlatools-console)/;', $path)) {
-    return "$base/$path";
-  }
   return NULL;
 }