(Reuters) - London's blue-chip index gave up early gains to turn lower on Wednesday, as dull Chinese data rekindled fears of a slowing global economy which were briefly kept in check after Washington decided to delay tariffs on some Chinese goods.The FTSE 100 index dipped 0.1% and the FTSE 250 midcap was flat by 0751 GMT.The Trump administration's move to delay 10% tariffs on Chinese goods lifted spirits, making up for some of the FTSE 100's rough start to the month following the Hong Kong..