doc: biblopgraphy update

Thanks to Anthony Towns for digging this up.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

doc/bitcoin.bib

@@ -19,10 +19,16 @@
 	year={2008}
 }
 @misc{BitcoinChannels,
+	title =	{{Instant TX for established business relationships (need replacements/nLockTime)}}
+July 04, 2011, 02:16:23 AM
+	urldate =	{2011-07-04},
+	note =	{\url{https://bitcointalk.org/index.php?topic=25786.0;all}}
+}
+@misc{PaymentChannels,
 	title =	{{Rapidly-adjusted (micro)payments to a pre-determined party}},
 	urldate =	{2015-07-13},
 	note =	{\url{https://en.bitcoin.it/wiki/Contract#Example_7:_Rapidly-adjusted_.28micro.29payments_to_a_pre-determined_party}}
-	}
+}
 @article{DBLP:journals/corr/DeckerW14,
   author    = {Christian Decker and
                Roger Wattenhofer},