By Mahmoud Mourad CAIRO (Reuters) - Former Egyptian President Hosni Mubarak will face a second and final retrial over the killing of protesters during the 2011 uprising that ended his 30-year rule, a high court said on Thursday. Mubarak, 87, was originally sentenced to life in prison in 2012 for conspiring to murder 239 demonstrators, sowing chaos and creating a security vacuum during the 18-day revolt, but an appeals court ordered a retrial. In that retrial, an Egyptian court in November dropped its case against him but the public prosecution appealed that.