libnetfilter_conntrack: fix static linking

It has a hardcoded -ldl link invocation, so drop it. Fixes:
http://autobuild.buildroot.net/results/66ba5f76694d0738b113463579ce6b2fa49a89d6/



Also add hash file and rename uclinux patch to new naming convention.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>