ENH: Only clean the backup directory on the first build of each day
ENH: Only clean the backup directory on the first build of each day

jcfr/CDash,jcfr/CDash,cpatrick/CDash,jcfr/CDash,jcfr/CDash,cpatrick/CDash,jcfr/CDash,cpatrick/CDash,cpatrick/CDash,cpatrick/CDash,cpatrick/CDash,jcfr/CDash