Make Firebird test reference correct database

[Krzmbrzl]

In the CI, a database called soci_test is created

soci/scripts/ci/before_build_firebird.sh

Line 9 in 9bcc5f8

echo 'CREATE DATABASE "LOCALHOST:/tmp/soci_test.fdb" PAGE_SIZE = 16384;' > /tmp/create_soci_test.sql

but the CMakeLists.txt for the Firebird test encoded a database name of test. Somehow this still worked on the CI, but it didn't work for me locally (invoking ctest directly).
Furthermore, using soci_test as the table name makes things more consistent with the tests for other backends.

[vadz]

I really don't understand how did it work before neither, could we be creating test.fdb somewhere else?

[Krzmbrzl]

Maybe the connection string is modified on the CI via some sort of environment variable or something like that?

[vadz]

Thanks for fixing this, finally merged.