Specify the permissions on sensu client config files

It turns out that salt-call inherits the umask from the user it is run
as, so if you ran `salt-call state.highstate` as root you would end up
with these files created as 0700 and sensu-client would break
Fix the perms on check files too
Merge pull request #10 from ministryofjustice/perms-fix

Specify the permissions on sensu client config files