shellcheck: Fix shellcheck SC2145

> Argument mixes string and array. Use * or separate argument.

- Swap echos for printfs and improve formatting
- Replace $@ with $*
- Split arrays into separate arguments

Signed-off-by: stevenhorsman <steven@uk.ibm.com>

tools/osbuilder/rootfs-builder/rootfs.sh

@@ -273,8 +273,8 @@ get_test_config() {
 	local config="${script_dir}/${distro}/config.sh"
 	source ${config}
 
-	echo -e "INIT_PROCESS:\t\t$INIT_PROCESS"
-	echo -e "ARCH_EXCLUDE_LIST:\t\t${ARCH_EXCLUDE_LIST[@]}"
+	printf "INIT_PROCESS:\t\t%s\n" "${INIT_PROCESS:-}"
+	printf "ARCH_EXCLUDE_LIST:\t\t%s\n" "${ARCH_EXCLUDE_LIST[@]:-}"
 }
 
 check_function_exist()