Wn ifdh location

jobsub v1_2s and earlier:

location where worker nodes ups setup file for ifdh is located. Example if wn_ifdh_location = /grid/fermiapp/products/common/etc/ then this file will be sourced in the wrapper script

jobsub v1_2t and later:

a list of locations,the wrapper file tries them one at a time until ifdh is located. NB if a list is given to v1_2s jobsub, it will source the first location on the list where hopefully ifdh can be located.