jammy-amd64-tf-a-build: Use set -x for better failure diagnostics

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Ib5783649742fa2a3f62439c71c3098537be68518
diff --git a/jammy-amd64-tf-a-build/Dockerfile b/jammy-amd64-tf-a-build/Dockerfile
index 4b85376..931ecd2 100644
--- a/jammy-amd64-tf-a-build/Dockerfile
+++ b/jammy-amd64-tf-a-build/Dockerfile
@@ -61,7 +61,7 @@
 COPY tf-*.install /tmp/
 COPY setup-sshd /usr/sbin/setup-sshd
 
-RUN set -e ;\
+RUN set -ex ;\
     echo 'locales locales/locales_to_be_generated multiselect C.UTF-8 UTF-8, en_US.UTF-8 UTF-8 ' | debconf-set-selections ;\
     echo 'locales locales/default_environment_locale select en_US.UTF-8' | debconf-set-selections ;\
     # Set Python 3 as default