LAGOS, Nigeria (Reuters) -- Nigerian oil unions began an unexpected two-day strike at Royal Dutch Shell Group facilities to protest against feared job cuts in the world's seventh largest oil exporter. Shell, which pumps about a million barrels a day of Nigeria's 2.3 million bpd output, said output and exports had not been affected. Unions said the action could be suspended early on Friday if talks between the two sides resumed, as expected. "The unions PENGASSAN and NUPENG have commenced a two-day industrial action. Efforts are being made to minimize the impact of this on the company's operations,'' a Shell...