Nope. Recall that, when you vote for president, you are NOT voting for the candidate. Instead, you are voting for the electors who represent the candidate's party.
Should Hillary be replaced, the party will simply instruct the electors to cast their ballots for her replacement. Further, ballots cast during early voting remain valid votes for the electors without reference to who the candidate may have been at the time they were cast.
True that, sorry, brain freeze! Should have known better!