Update .travis.yml

Install libmyodbc. Set CMwke property SOCI_ODBC_TEST_MYSQL_CONNSTR.
Update src/backends/odbc/test/test-mysql.dsn

Try minimal DSN settings on travis-ci.org
Update .travis.yml to configure libmyodbc driver
Typo
dpkg-reconfigure firebird2.5-super
Run dpkg-reconfigure as root