resolved: rename manager_our_packet() → manager_packet_from_local_address()

resolved: rename manager_our_packet() → manager_packet_from_local_address()

Let's be more precise in naming this function, after all this doesn#t
actually check if the packet is really ours, but just that the source IP
address is a local one. Hence name it that way.

(This is preparation to add a helper that checks if packet belongs to
local transaction later on)