Update SUSY15TriggerList.py to include electron triggers for VH(4b) analysis.

The VH(4b) analysis is requesting to add the 3 electron triggers in their DRAW_RPVLL filter to the SUSY15TriggerList. These events are required for our analysis and does not significantly increase the downstream size since SUSY15 is seeded by the DRAW_RPVLL event stream.

Tagging: @jstupak, @cohm, @ctreado, @martindl, @kpachal, @jdandoy, @jmontejo, @calpigia, @alopezso, @leejr, @fladias, and @crizzi