Wrong URLs in the IE devbuild update manifest

[fhd]

The devbuild update manifest we currently generate looks like this:

{
  "adblockplusie/win64": {
    "url": "https://adblockplus.org/devbuilds/adblockplusie/adblockplusie-1.2.667.exe?update",
    "version": "1.2.667"
  },
  "adblockplusie/msie64": {
    "url": "https://adblockplus.org/devbuilds/adblockplusie/adblockplusie-1.2.667.exe?update",
    "version": "1.2.667"
  },
  "adblockplusie/msie32": {
    "url": "https://adblockplus.org/devbuilds/adblockplusie/adblockplusie-1.2.667.exe?update",
    "version": "1.2.667"
  },
  "adblockplusie/win32": {
    "url": "https://adblockplus.org/devbuilds/adblockplusie/adblockplusie-1.2.667.exe?update",
    "version": "1.2.667"
  }
}

Instead of pointing to the .exe files, we should point to the architecture specific .msi files.

While we're at it, we can also remove the win32 and win64 entries, they're not used anymore.

[fhd]

Pushed: ​https://hg.adblockplus.org/sitescripts/rev/0fd76b99fcc1