build: always install files into /etc/libnl
build: always install files into /etc/libnl

I observed that with the RedHat build target in the Open Build
Service, files were put into /etc rather than /etc/libnl.
Self-referential variables are a bad idea, and so just avoid this.

karlhiramoto/libnl,HolyShitMan/libnl-1,congwang/libnl,dsahern/libnl,socketpair/libnl,tgraf/libnl,claudelee/libnl,dsahern/libnl,cfriedt/libnl,thom311/libnl,Distrotech/libnl,teto/libnl_old,mshirley/libnl,tklauser/libnl,Distrotech/libnl,Distrotech/libnl,cyclops8456/libnl3,mshirley/libnl,karlhiramoto/libnl,greearb/libnl-ct,kolyshkin/libnl,UnicronNL/libnl3,kolyshkin/libnl,vyos/libnl3,tklauser/libnl,claudelee/libnl,baloo/libnl,socketpair/libnl,honsys/libnl,tklauser/libnl,tklauser/libnl,vyos/libnl3,UnicronNL/libnl3,houstar/libnl,tgraf/libnl,HolyShitMan/libnl-1,cyclops8456/libnl3,karlhiramoto/libnl,chitranshi/libnl,cyclops8456/libnl3,tgraf/libnl,cfriedt/libnl,cfriedt/libnl,cyclops8456/libnl3,dsahern/libnl,honsys/libnl,baloo/libnl,houstar/libnl,baloo/libnl,kolyshkin/libnl,vyos/libnl3,vyos/libnl3,UnicronNL/libnl3,congwang/libnl,teto/libnl_old,mshirley/libnl,honsys/libnl,chitranshi/libnl,greearb/libnl-ct,claudelee/libnl,thom311/libnl,claudelee/libnl,houstar/libnl,Distrotech/libnl,baloo/libnl,dsahern/libnl,congwang/libnl,mshirley/libnl,thom311/libnl,HolyShitMan/libnl-1,HolyShitMan/libnl-1,greearb/libnl-ct,teto/libnl_old,tgraf/libnl,chitranshi/libnl,houstar/libnl,cfriedt/libnl,chitranshi/libnl,teto/libnl_old,socketpair/libnl,congwang/libnl,kolyshkin/libnl,karlhiramoto/libnl,honsys/libnl,UnicronNL/libnl3