Supersede svirt_sandbox_file_t by container_file_t

Summary:
The svirt_sandbox_file_t type is deprecated.

Fixes T1418.

Test Plan: Apply states on Equatower

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1418

Differential Revision: http://devcentral.nasqueron.org/D1743