kernel: test: improve error handler

print output from  last command that failed.

Signed-off-by: Jose Carlos Venegas Munoz <jose.carlos.venegas.munoz@intel.com>

kernel/build-kernel.sh

@@ -296,10 +296,10 @@ main() {
 	if [ -z "${kernel_path}" ]; then
 		config_version=$(get_config_version)
 		kernel_path="${PWD}/kata-linux-${kernel_version}-${config_version}"
+		info "Config version: ${config_version}"
 	fi
 
 	info "Kernel version: ${kernel_version}"
-	info "Config version: ${config_version}"
 
 	case "${subcmd}" in
 	build)

kernel/build-kernel_test.sh

@@ -7,6 +7,7 @@
 set -o errexit
 set -o nounset
 set -o pipefail
+set -o errtrace
 
 readonly script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 readonly build_kernel_sh="${script_dir}/build-kernel.sh"
@@ -17,6 +18,16 @@ exit_handler() {
 }
 trap exit_handler EXIT
 
+err_report() {
+	echo "Error:"
+	echo "line: $1"
+	echo "Last saved output:"
+	echo "${out:-}"
+}
+
+trap 'err_report $LINENO' ERR
+
+
 OK() {
 	echo "OK"
 }