Increased version number and the version required

This was done because the previous commit that removed the
deprecated functions in index.php only works in 2.4 onwards.
Removed unnecessary checks since we increased the version required
Removed unnecessary setting of parameter in course module object

This caused a debugging message to be thrown in 2.6.
Merge branch 'MOODLE_25_STABLE' into MOODLE_25_BFC