executor: Don't KeyError if no duration provided in wlspec
executor: Don't KeyError if no duration provided in wlspec

mdigiorgio/lisa,ARM-software/lisa,ARM-software/lisa,credp/lisa,bjackman/lisa,credp/lisa,ARM-software/lisa,arnoldlu/lisa,joelagnel/lisa,arnoldlu/lisa,mdigiorgio/lisa,ARM-software/lisa,joelagnel/lisa,credp/lisa,credp/lisa,bjackman/lisa