omg... that's so sad seriously... what is this world Lady Gaga's 30th bash didn't end well for her producer DJ White Shadow, who had $15k worth of gear jacked outside the party ... according to cops.  White Shadow -- who produced Gaga's "Born This Way" and "ARTPOP" albums -- had been on deck duty at the No Name Club event with a ton of A-listers in attendance. According to the police report ... around 4 AM White Shadow and a pal were leaving the venue with all his gear when they g