just build for windows' target.

Author: huangjj27

appveyor.yml

@@ -15,9 +15,8 @@ environment:
     secure: q8Wqx0brgfpOYFQqWauvucE2h0o1WYb41a3gKaCKV9QiE4eTz6qLNlqyC3mdsp4Q
 branches:
   only:
-  #   - master
-    # - auto
-    - ci-appvoyer
+    - master
+    - auto
 
 install:
   # If this is a PR and we're not allowed to test PRs, skip the whole build.
@@ -72,7 +71,3 @@ build: false
 
 test_script:
   - cargo build --release --target %TARGET% %FEATURES%
-  - cargo test --release -p rustup-dist --target %TARGET%
-  - cargo test --release --target %TARGET% %FEATURES%
-  - if defined BUILD_MSI pushd src\rustup-win-installer && cargo build --release --target %TARGET% & popd
-  - if defined BUILD_MSI pushd src\rustup-win-installer\msi && powershell .\build.ps1 -Target %TARGET% & popd