CI: fix appveyor build
CI: fix appveyor build

http://help.appveyor.com/discussions/problems/6312-curl-command-not-found
https://www.appveyor.com/docs/how-to/download-file/

himikof/intellij-rust,alygin/intellij-rust,alygin/intellij-rust,d9n/intellij-rust,anton-okolelov/intellij-rust,d9n/intellij-rust,intellij-rust/intellij-rust,Undin/intellij-rust,d9n/intellij-rust,alygin/intellij-rust,himikof/intellij-rust,Undin/intellij-rust,alygin/intellij-rust,himikof/intellij-rust,intellij-rust/intellij-rust,anton-okolelov/intellij-rust,himikof/intellij-rust,anton-okolelov/intellij-rust,Undin/intellij-rust,Undin/intellij-rust,intellij-rust/intellij-rust,d9n/intellij-rust,anton-okolelov/intellij-rust,anton-okolelov/intellij-rust,himikof/intellij-rust,intellij-rust/intellij-rust,Undin/intellij-rust,alygin/intellij-rust,Undin/intellij-rust,d9n/intellij-rust,intellij-rust/intellij-rust,intellij-rust/intellij-rust