add additional ELC exclusions from upstream CentOS tests

upstreamcentostests.sh

@@ -67,7 +67,12 @@ DELIM
 # Disable obvious CentOS jobs for elc distros ...
 LSB_DISTRO_ID=`lsb_release -si`
 if [ "$LSB_DISTRO_ID" != "CentOS" ]; then
+  # Performs tests on /etc/centos-release and friends
   echo "8|tests/p_centos-release/*|Not applicable on $LSB_DISTRO_ID" >> ./skipped-tests.list
+  # Checks if the kernel secure boot signing key is 'CentOS'
+  echo "8|tests/p_kernel/*|Not applicable on $LSB_DISTRO_ID" >> ./skipped-tests.list
+  # Uses /etc/centos-release as an input file
+  echo "8|tests/r_pdf/01_pdf-test*|Not applicable on $LSB_DISTRO_ID" >> ./skipped-tests.list
 fi
 
 # Tweaks for test suite to work on CERN CentOS