Exchange traded funds provider, Barclays Bank has agreed to sell its iShares asset management business to private equity firm CVC Capital Partners for £3 billion as it looks to raise cash and avoid turning to the government for aid.   However, Barclays will still maintain links with iShares, and is providing £2.1 billion of financing for the deal - in effect a loan to CVC to help it buy iShares.   "This transaction realises significant value for Barclays," said the bank's chief executive John Varley.