inc/ipsec: proper softcoding for tmp_path
inc/ipsec: proper softcoding for tmp_path

This allows us to grep for the file name as "name.something.xml"
and still be able to find the variable or path or binary or so,
while the actual file name is only set once avoiding typos in the
process as well...

opnsense/core,opnsense/core,opnsense/core,opnsense/core,opnsense/core,opnsense/core