Should set permissive umask before exec.

[pillarsdotnet]

In my use-case, we have a restrictive umask 0027 as required by CIS security-hardening standards. Puppet (and thus puppet-python inherits this umask. The files installed by pip are affected by this umask.

In order to make installed Python pips available to non-root users, this module should set a permissive umask such as 0002 or 0022 before invoking pip.