fix db_update_sqn(): reset stmt in all error cases

Use the common db_bind_int64() so that the stmt bindings are cleared for any
errors and to get error logging for free.

On error with sqlite3_step(), log the SQL error message, and make sure the stmt
is cleared of bindings and reset.

After sqlite3_step(), verify that exactly one row was modifed, log and return
errors otherwise.

After this patch, the DB interaction closely matches the other (refactored) DB
functions.

Change-Id: I0d870d405e2e0a830360d9ad19f0a3f9e09d8cf2
4 files changed