Hold the Vivendi IPO. It appears that talks between the French infrastructure company and GE over Vivendi’s 20 percent stake in NBC Universal are back on. A deal would clear the way for GE to complete its spinoff of the rest of NBC U to Comcast. But that may not be the end of the media M&A mania. Analysts and industry insiders are speculating about a possible rash of mega-mergers, including a possible Time Warner-Viacom tie-up, a Discovery-Scripps pairing and a takeover of Vodafone by Verizon.