Close databases in onStop user

The key is evicted before onCleanup. To be safe we should close db in
onStopUser while the key is still available

Test: switch to u10, switch to u0, am stop-user 10, am switch-user 10
Bug: 37781320
Change-Id: Iab18c503a236a15833974b0dad2af6eed86a6c02
1 file changed