Fixed AppVeyor configuration

appveyor.yml

@@ -24,7 +24,7 @@ install:
   - curl -sSf -o rustup-init.exe https://dev-static.rust-lang.org/rustup/dist/i686-pc-windows-gnu/rustup-init.exe
   - rustup-init.exe -y
   - set PATH=%PATH%;C:\Users\appveyor\.cargo\bin
-  - rustup default nightly-2016-05-10-x86_64-pc-windows-msvc
+  - rustup default stable-x86_64-pc-windows-msvc
 
   # Install the target we're compiling for
   - if NOT "%TARGET%" == "x86_64-pc-windows-msvc" rustup target add %TARGET%
@@ -56,10 +56,11 @@ test_script:
   - ps: |
       if($env:BUILD_MSI) {
         cd src\rustup-win-installer
-        cargo build --release
+        cargo build --release --target %TARGET%
         cd msi
         .\build.ps1
         cd ..\..\..
+        if($LastExitCode -ne 0) { $host.SetShouldExit($LastExitCode) }
       }
 
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