European shares hold on to small gains ahead of Fed announcement

* FTSEurofirst 300 up 0.3 pct * Fugro tumbles 26 pct after cancelling payout * Total and Schneider up after results By Francesco Canepa LONDON, Oct 29 (Reuters) - European stocks held on to small gains on Wednesday, as optimism ahead of a U.S. Federal Reserve policy announcement outweighed further gloom for the oil exploration industry. Dutch marine services group Fugro sank 26 percent after it warned it would not pay a dividend for 2014 due to deteriorating markets and pri