Remove accounts.privkeys_hex from default config
Remove accounts.privkeys_hex from default config

There should be no need to have those in config.

gsalgado/pyethapp,ethereum/pyethapp,gsalgado/pyethapp,changwu-tw/pyethapp,ethereum/pyethapp,RomanZacharia/pyethapp,RomanZacharia/pyethapp,changwu-tw/pyethapp