when sqlite returns SQLITE_OK on SQLITEStatement.execute(), ignore it

if it is not ignored AND if SQLITEStatement.execute() is called with a SELECT
or a pragma or some sql statement that returns data, caller gets an exception
with a weird error: "error code 100: unknown error"
to avoid confusion generated by this exception, just write a warning
and ignore the returned data.
Change-Id: I8f0225ceff8f92e32a58f323551e5ada6df63593