In FORWARD_LOCAL_FAILED case, we can get the failcode and can't get the resolve time, that is different with FORWARD_FAILED case.

It's a optional field. We only set failcode for FORWARD_LOCAL_FAILED case, and set this field with 0 in other case.

…ayment_add()

…ents_get()

Here I add the test for this 5 local_failed case in this commit.
There 5 cases for FORWARD_LOCAL_FAILED status:
    1. When Msater resolves the reply about the next peer infor(sent by Gossipd), and need handle unknown next peer failure in channel_resolve_reply();
    2. When Master handle the forward process with the htlc_in and the id of next hop, it tries to drive a new htlc_out but fails in forward_htlc();
    3. When we send htlc_out, Master asks Channeld to add a new htlc into the outgoing channel but Channeld fails. Master need handle and store this failure in rcvd_htlc_reply();
    4. When Channeld receives a new revoke message, if the state of corresponding htlc is RCVD_ADD_ACK_REVOCATION, Master will tries to resolve onionpacket and handle the failure before resolving the next hop in peer_got_revoke();
    5. When Onchaind finds the htlc time out or missing htlc, Master need handle these failure as FORWARD_LOCAL_FAILED in if it's forward payment case.