Refactor travis: Build on minimal image (#243)

* Attempt 1

* minimal → generic

* Add -y to rustup script

* Remove clang

* Refactor.

* Remove CARGO_TARGET_DIR for now

* Display versions of tools from the rust toolchain

* Fix

substrate/ci/script.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+set -eux
+
+# Install rustup and the specified rust toolchain.
+curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain=$RUST_TOOLCHAIN -y
+
+# Load cargo environment. Specifically, put cargo into PATH.
+source ~/.cargo/env
+
+rustc --version
+rustup --version
+cargo --version
+
+case $TARGET in
+	"native")
+		sudo apt-get -y update
+		sudo apt-get install -y cmake pkg-config libssl-dev
+
+		cargo test --all
+		;;
+
+	"wasm")
+		# Install prerequisites and build all wasm projects
+		./init.sh
+		./build.sh
+		;;
+esac