dmlib: changed array access to keyed instead of ordinal.
dmlib: changed array access to keyed instead of ordinal.

This supports the move to ADODB_FETCH_ASSOC instead of ADODB_FETCH_BOTH.
see:
http://docs.moodle.org/en/XMLDB_Problems#ADOdb_fetch_mode_.28ASSOC.2C_NUM_and_BOTH.29

Author: Luke Hudson <6b3799be4300e44489a08090123f3842e6419da5@catalyst.net.nz>

dilawar/moodle