By Ayman al-Warfalli BENGHAZI, Libya (Reuters) - Libya's internationally recognized parliament voted on Monday to reject a unity government proposed under a U.N.-backed plan to resolve the country's political crisis and armed conflict. The rejection was widely expected, but signaled that mediators still face a steep challenge in winning support for a new government. Since 2014, Libya has had two competing parliaments and governments, one based in Tripoli and the other in the east.