Skip p_shim, it was not relevant and its skipping message was misleading

upstreamcentostests.sh

@@ -66,6 +66,7 @@ cat > ./skipped-tests.list  <<DELIM
 8|tests/p_samba/*|No systemd therefore cannot be tested
 8|tests/p_selinux/*|Not applicable in C8 containers
 8|tests/p_sendmail/*|No systemd therefore cannot be tested
+8|tests/p_shim/*|No bootloader involved, boot path is always deleted so there is no secureboot
 8|tests/p_squid/*|squid seems to always fail, disabling for now
 8|tests/p_squirrelmail/0-install_squirrelmail.sh|No systemd therefore cannot be tested
 8|tests/p_syslog/*|No rsyslog installed, also not relevant on containers