Change the mask used when creating temporary files from 777 to 700, to prevent

Change the mask used when creating temporary files from 777 to 700, to prevent
an obscure race-condition security hole where a file may for a short time
have the wrong group.  Could have used 707 instead but that's just too weird
of a permission.  The define name used to be ACCESSPERMS but that is defined
as 777 on Linux, so changed the name to INITPERMMASK.