doc: Remove outdated information about boost versions

Bitcoin core should work with any remotely recent boost version
if a proper build environment is present. Remove a confusing comment
from the build documentation.

Rebased-From: bd45b1a

Conflicts:
	doc/build-unix.md

doc/build-unix.md

@@ -68,11 +68,7 @@ for Ubuntu 12.04 and later:
 
 	sudo apt-get install libboost-all-dev libdb5.1-dev libdb5.1++-dev
 
-for Ubuntu 13.10:
-	libboost1.54 will not work,
-	remove libboost1.54-all-dev and install libboost1.53-all-dev instead.
-
-for other Debian:
+for Debian 7 (Wheezy) and later:
 
 	sudo apt-get install libdb5.1-dev
 	sudo apt-get install libdb5.1++-dev