ec67456172 Fix CJDNS marker byte check (Ava Chow)
Pull request description:
Only the first byte of a CJDNS address is 0xfc, the second byte should be ignored.
See https://github.com/hyperboria/peers for examples of CJDNS addresses.
ACKs for top commit:
apoelstra:
ACK ec67456172
sanket1729:
urACK ec67456172.
Kixunil:
ACK ec67456172
Tree-SHA512: 0da1054a8e997b6bf6e0aaedc40943edb6a6c7b23f660c92b34dc9395e6153e7e10b0268335a77fbcb5bb635352e1ed92839b350188fd6d33dabe558e88c00bb