Fixing bug with in-memory SQLite storage
Fixing bug with in-memory SQLite storage

This change swaps out the in-memory SQLite database for file-based data
storage. SQLAlchemy support for in-memory SQLite storage does not work
across threads. The new storage scheme stores all PyKMIP server data in
/tmp.

viktorTarasov/PyKMIP,OpenKMIP/PyKMIP,OpenKMIP/PyKMIP,viktorTarasov/PyKMIP