db: Switch from 'synchronous = FULL' to 'synchronous = NORMAL'

As we're using WAL mode, it is not neccessary to use synchronous=FULL
but rely on synchronous=NORMAL mode while still guaranteeing database
consistency.

To do this, we can fix the typo in one of our two PRAGMA statements,
and remove the other.

See https://www.sqlite.org/pragma.html#pragma_synchronous for the
sqlite3 documentation on that topic.

Change-Id: Ie782f0fe90e7204c4d55cdb3948b728c348367d1
Closes: OS#5566
RelateD: OS#5564, OS#5563
1 file changed