contrib: force boost to be build

This patch remove the forcing on GNU/Linux platforms
to use the system provided boost.
This causes the boost deps to always be compiled.
This solves many issues with badly installed systems.

Change-Id: Ia6725882b09e9d19837da382c9c3afb88e735096

contrib/src/boost/rules.mak

@@ -3,11 +3,6 @@ BOOST_VERSION := 1_61_0
 BOOST_URL := https://downloads.sourceforge.net/project/boost/boost/1.61.0/boost_$(BOOST_VERSION).tar.bz2
 
 PKGS += boost
-ifdef HAVE_LINUX
-ifndef HAVE_ANDROID
-PKGS_FOUND += boost
-endif
-endif
 
 BOOST_B2_OPTS := variant=release \
 				 link=static \