Shares of JetBlue Airways Corp. took a hard hit Tuesday, following an analyst’s call to sell the stock, and after the air carrier announced that its long-time chief executive was retiring for health reasons.A look at the stock’s JBLU, -10.65% chart suggests, however, that the downgrade may have had more to do with the selloff, as shares initially gained on the CEO news. JetBlue’s stock ticked up after CEO-succession announcement, then dived in the wake of BofA Securities’ call to sell. FactSet, MarketWatc ...