UBUNTU: SAUCE: Dump stack when X.509 certificates cannot be loaded

BugLink: https://bugs.launchpad.net/bugs/1932029

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
(cherry picked from commit b5b4085dc5)
(xnox: cherry-pick is from impish:linux SAUCE)
Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

certs/common.c

@@ -41,6 +41,7 @@ int load_certificate_list(const u8 cert_list[],
 		if (IS_ERR(key)) {
 			pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
 			       PTR_ERR(key));
+			WARN_ON_ONCE(1);
 		} else {
 			pr_notice("Loaded X.509 cert '%s'\n",
 				  key_ref_to_ptr(key)->description);