It's impossible to say what he meant, but it seems pretty unlikely that he'd spit there had they not been having a barney at the time. How often will a footballer spit that close to a player when he could turn his head an inch or two and miss him by three or four feet? It looked like one of those where he deliberately spat near him, but not at him. A sort of "piss off, you twat" spit, rather than actively trying to gob on him. After all, no matter how ropey he's been this season, it's hard to believe he could miss him from there if he was trying to hit him.
Who knows, though. Daft thing to do. Equally it doesn't bother me as much as, say, a really bad challenge, or almost everything every manager in the league says in interviews after games.