By David Ljunggren OTTAWA (Reuters) -Canadian Prime Minister Justin Trudeau on Monday said his government still needed temporary emergency powers in the wake of a truckers’ blockade, citing “real concerns” about threats in the days ahead. Trudeau told a televised news conference there were signs some truckers were regrouping outside the capital Ottawa and might come back to try to restart a three-week occupation that brought downtown Ottawa to a halt. The protesters initially wanted an end to cross-border COVID-19 vaccine mandates for truck drivers, but the occupation turned into a demonstrati…