sqlite: setting isolation level to autocommit for PRAGMAs
sqlite: setting isolation level to autocommit for PRAGMAs

This resolves a regression as safety level may not be changed
within a transaction as the transaction block was opened
implicitly and auto-commit has been removed in python 3.6.
https://bugs.python.org/issue28518

After the PRAGMA block we restore the isolation level to the
previous value (default is magic mode).

anthraxx/arch-security-tracker,archlinux/arch-security-tracker,jelly/arch-security-tracker,anthraxx/arch-security-tracker,jelly/arch-security-tracker,anthraxx/arch-security-tracker,archlinux/arch-security-tracker