That's what happens when you pick a running mate to appease the establishment wing of your party. It's a good move from the standpoint of short-term political gain (so that you don't have your own party actively trying to sabotage your campaign, as establishment Republicans are doing to Trump), but in the long run it just helps empower the establishment. That's why I really hope that Trump doesn't try to appease the establishment of the GOP by picking a running mate like Rubio etc, because then the party hack can use the Vice Presidency as a launchpad for his own career and his family/allies, as the Bushes did with Reagan.
First heard about Armitage in this: http://newsok.com/article/2192079