bump rustc and adjust for rustc-dev component

(also sync AppVeyor with Travis: use stable cargo)

Author: RalfJung

.appveyor.yml

@@ -32,7 +32,7 @@ install:
     - rustup update
     # Install "master" toolchain
     - cargo install rustup-toolchain-install-master & exit 0
-    - rustup-toolchain-install-master -f -n master %RUSTC_HASH% -c cargo -c rust-src
+    - rustup-toolchain-install-master -f -n master %RUSTC_HASH% -c rust-src -c rustc-dev
     - rustup default master
     - rustc --version
     - cargo --version

.travis.yml

@@ -39,7 +39,7 @@ before_script:
 - rustup update
 # Install "master" toolchain
 - cargo install rustup-toolchain-install-master || echo "rustup-toolchain-install-master already installed"
-- travis_retry rustup-toolchain-install-master -f -n master $RUSTC_HASH -c rust-src
+- travis_retry rustup-toolchain-install-master -f -n master $RUSTC_HASH -c rust-src -c rustc-dev
 - rustup default master
 - rustc --version
 - cargo --version