changing api_get_datetime function by api_get_utc_datetime -refs #7131
Merge branch 'yoselyn.7137' of github.com:ycastillo/chamilo-lms into ycastillo-yoselyn.7137
Merge branch '1.9.x' of github.com:chamilo/chamilo-lms into ycastillo-yoselyn.7137
Merge datetime function calls changes - refs #7131