Removed database specification from tests.

Previously tests failed when users specify database name with DBI environmental variable
since some test codes explicitly had `test' as database name.

$ # Here using `q4m_test'. Now this works if q4m_test database is already created.
$ DBI='dbi:mysql:database=q4m_test;host=localhost'  DBI_USER='root' DBI_PASSWORD='' make test