LONDON (Reuters) - AstraZeneca is fully on track to reach its earnings goal for next year, its chief executive told Reuters on Friday after the British drugmaker's quarterly earnings missed market expectations."What we've said is that by 2021 we would cover the dividend in full and we would target an operating margin north of 30%. This is very much in line with what we are targeting," CEO Pascal Soriot said, following the release of fourth-quarter results.AstraZeneca is moving into a third..