Fix pathPrefix causing erroneous redirects (#7871)
Fix pathPrefix causing erroneous redirects (#7871)

* Fix pathPrefix causing erroneous redirects

* Don't write __PATH_PREFIX__ to the window.page object

ChristopherBiscardi/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,mingaldrichgan/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,0x80/gatsby,gatsbyjs/gatsby