Create staging directory for Staging Manager.

Staging Manager is a high-level service (yet to be committed) that
manages multi-package sessions requiring a reboot to be applied, for
example if one of the packages is an APEX file. This directory will
contain the session data and the temporary copies of the packages.

Bug: 118865310
Test: N/A
Change-Id: I8aceefab849cf5af17086cb6868b801d1c2615e9
1 file changed