skip removing entries from sqlite if store-queue-on-shutdown is used

[sni]

if --store-queue-on-shutdown is used, database should only be accessed during shutdown and on initial startup. Skipping the done() saves the unnecessary query preparation, database locks, etc...

• fixes #369

[esabol]

CI tests pass, so I think we're good to merge here. The changes look good to me, but I haven't personally tested them. @sni , have you tested these changes on your system? And they work as desired?

[sni]

yes, works as expected.