Workaround AppVeyor publish issue

Work around issue with publishing NuGet packages from AppVeyor.
See http://help.appveyor.com/discussions/problems/8215-cannot-publish-to-nuget-get-400-bad-request-error

appveyor.yml

@@ -4,6 +4,8 @@ version: 1.0.{build}
 environment:
   DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
   NUGET_XMLDOC_MODE: skip
+  NUGET_API_KEY:
+    secure: 6MzbzEs4YdJKS67Gio5gEO8mNKmwfC4UHTCmECZ1KOutI6ndm4vAECazmVNB6an7
 
 branches:
   only:
@@ -26,12 +28,17 @@ nuget:
 skip_tags: false
 test: off
 
-deploy:
-
-  - provider: NuGet
-    api_key:
-      secure: 6MzbzEs4YdJKS67Gio5gEO8mNKmwfC4UHTCmECZ1KOutI6ndm4vAECazmVNB6an7
-    artifact: /.*\.nupkg/
-    skip_symbols: false
-    on:
-      appveyor_repo_tag: true
+deploy_script:
+  - appveyor DownloadFile https://dist.nuget.org/win-x86-commandline/latest/nuget.exe  
+  - ps: if ($env:APPVEYOR_REPO_TAG -ne "false") { ($artifacts.values | Where-Object {($_.path -like '*.nupkg') -and  !($_.path -like '*.symbols.nupkg')}) | foreach-object {nuget.exe push $_.path -Source https://www.nuget.org/api/v2/package -ApiKey $env:NUGET_API_KEY; if ($lastexitcode -ne 0) {throw}}}
+
+#deploy:
+#
+#  - provider: NuGet
+#    api_key:
+#      secure: 6MzbzEs4YdJKS67Gio5gEO8mNKmwfC4UHTCmECZ1KOutI6ndm4vAECazmVNB6an7
+#    artifact: /.*\.nupkg/
+#    skip_symbols: false
+#    on:
+#      appveyor_repo_tag: true
+#