Update run_eb_eb_and_eb_ee_fit.py

Add in background_ele27.txt which is needed to run
run_eb_eb_and_eb_ee_fit.py.

run_eb_eb_and_eb_ee_fit.py now covers all pt bins (it missed one
previously).

run_eb_eb_and_eb_ee_fit.py makes a random temporary directory for
plotting output.