Only update source address when resolving is successful in ibcore.

When resolving an IP address in ibcore, only update the source address
upon normal completion. The ibcore address resolve function does not
care about the scope ID value of the IPv6 link-local addresses and expects
this information has already been extracted into the bound_dev_if field.
Because the same IPv6 link-local address can exist on multiple interfaces
the ibcore address resolver gets confused and returns ENETUNREACH.

Instead of updating both source address and bound_dev_if just keep the
address set to any address until resolving completes. For the sake of code
symmetry a similar change has been applied to the IPv4 address resolve path.

MFC after: 1 week
Sponsored by: Mellanox Technologies