Initialize directory delayed in shared code and add checks to verify
that it is valid. Close attached / cloned databases to prevent locks
on files and leaking temporary directories caused by SQLite:
QTemporaryDir: Unable to remove "...\Temp\tst_qsqldatabase-P1XkOA" most likely due to the presence of read-only files.
QTemporaryDir: Unable to remove "...\Temp\tst_qsqltablemodel-P1XkOA" most likely due to the presence of read-only files.
QWARN : tst_QSql::concurrentAccess() QTemporaryDir: Unable to remove "...\Temp\tst_qsql-l0VAKJ" most likely due to the presence of read-only files.
Change-Id: If85bbaed04bb1a32e427d642be332996d967f796
Reviewed-by: Andy Shaw <andy.shaw@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>