Refs #808 Fixing Config.test.php when ran in all_tests.php. Side effect due to setTestEnvironment(). Renamed test config section from Global (which is a special case in test environment) to GlobalSection

git-svn-id: http://dev.piwik.org/svn/trunk@2433 59fd770c-687e-43c8-a1e3-f5a4ff64c105