The main purpose of function ccEpFunc is to compute chaincode
endpoint and return error if needed. It will be better to do
all checks and computation during the node start up phase.

The CR will do all the necessary checks in node/start.go and
panic if unexpected error. Therefore, it will pass only the
chaincode endpoint value (as string) to the follow up function.

Also, the CR moves panic from createChaincodeServer to serve
function and revises UT to cover all chaincode endpoint
computation cases.

Change-Id: Ie4802472f0dd04c3a3da1e1ac6e30f90463fb0b2
Signed-off-by: Boliang Chen <cblsjtu@gmail.com>