Fix api's calls to api v2 in core files

Currently in core we still use v2 api's, but in few places there is call to v3 api's which might break few functionality since code is not migrated to work with v3 api. So we should revert that code to use v2 api's

check http://forum.civicrm.org/index.php/topic,19724.msg82246.html#msg82246
Also check other places in https://fisheye2.atlassian.com/changelog/CiviCRM?cs=32817

We should also grep and check if there are any more places.