What a cash-swipe! A subway security guard hired to crack down on rampant fare evasion was caught on camera swiping in riders with a student OMNY card in exchange for cash. A new report from MTA Inspector General Daniel Cort’s office showed the guard tapping straphangers through the gates of a Brooklyn station — using a stolen Department of Education OMNY card that was intended for student use. The IG’s report released Thursday did not identify the security guard, who was removed from the