mirror.pkgbuild.com: redirect North/South America to Germany

mex.mirror.pkgbuild.com suffers from a disk failure so it can't act as a
proper mirror at the moment.

roles/mirror_load_balancer/templates/nginx.d.conf.j2

@@ -7,9 +7,9 @@ map $geoip2_data_continent_name $preferred_upstream {
     'Africa' ger.mirror.pkgbuild.com;
     'Asia' jpn.mirror.pkgbuild.com;
     'Europe' ger.mirror.pkgbuild.com;
-    'North America' mex.mirror.pkgbuild.com;
+#    'North America' mex.mirror.pkgbuild.com;
     'Oceania' sgp.mirror.pkgbuild.com;
-    'South America' mex.mirror.pkgbuild.com;
+#    'South America' mex.mirror.pkgbuild.com;
 }
 
 log_format loadbalancer