Add openssl to AppVeyor env

.appveyor.yml

@@ -5,7 +5,7 @@ environment:
   - TARGET: x86_64-pc-windows-gnu
   - TARGET: i686-pc-windows-gnu
 install:
-  - cinst mingw
+  - cinst openssl.light
   - ps: Start-FileDownload "https://static.rust-lang.org/dist/rust-nightly-${env:TARGET}.exe" -FileName "rust-nightly.exe"
   - ps: .\rust-nightly.exe /VERYSILENT /NORESTART /DIR="C:\rust" | Out-Null
   - ps: $env:PATH="$env:PATH;C:\rust\bin"
@@ -13,4 +13,4 @@ install:
   - cargo -vV
 build: false
 test_script:
-  - cargo test --verbose --no-default-features
+  - cargo test --verbose