Set commit based on code-server instead of VS Code

This ensures it'll be different for each build, otherwise it would also
be the same as long as the VS Code version is the same.

scripts/tasks.bash

@@ -57,6 +57,8 @@ function prepend-loader() {
 function build-code-server() {
 	copy-server
 	local min=""
+	export BUILD_SOURCEVERSION
+	BUILD_SOURCEVERSION=$(node -p "require('${sourcePath}/build/lib/git.js').getVersion('${rootPath}')")
 	if [[ -n "${minify}" ]] ; then
 		min="-min"
 		yarn gulp minify-vscode --max-old-space-size=32384