CI: Add PR variable to jenkins script for clarity
CI: Add PR variable to jenkins script for clarity

Add a variable that holds the PR number to improve code clarity in the
Jenkins setup script.

Signed-off-by: James O. D. Hunt <348fbaadfbada55ea105602bf5609e23ac1c4898@intel.com>

devimc/tests,clearcontainers/tests,clearcontainers/tests,devimc/tests,chavafg/tests,chavafg/tests