No, its never been stated as canned. Wiki says:
"With the announcement of the PlayStation 4 on 20 February 2013, there was an expectation that Agent may have moved to become an exclusive PlayStation 4 title. However, there was no mention of the game at the launch, but developer Rockstar had signed up to support the PlayStation 4. When asked if Agent was still a PlayStation 3 title after the press conference of the PlayStation 4 reveal during a roundtable media session, Sony Worldwide Studios boss Shuhei Yoshida said "You are asking the wrong person. I have some knowledge, but I'm not in a position to talk about it."