The dbaccess unoapi test calls
css::sdb::XSingleSelectQueryComposer::appendFilterByColumn
in a state where there is no current row, and thus no column value.
This does not make sense, but let's not break the build while I
figure out how to fix the unoapi test.

Change-Id: If813a1544ec9a5dac6f87197982d10576c91cd8c