For two hours last night, there was a flashback of CNN’s former glory as the cable news leader thriving on covering big breaking stories. Form 11 PM-12AM ET, when the news of the killing of Osama bin Laden was breaking, including President Barack Obama confirming it in his address, CNN drew massive 7.8 million viewers. Fox News Channel was second with 4.8 million, followed by MSNBC with 2.3 million. From 12-1 AM ET, CNN continued to lead with 5.3 million vs. 3.5 million for FNC and 1.9 million for MSNBC. For FNC, this marked the highest-rated Sunday night since the April 6, 2003 invasion of Baghdad. Now if CNN could only find a way to sustain its audiences beyond breaking news …