Revert "dpkg-shlibdeps: warning: dependency on libnsl.so.1 [..]"

Revert "dpkg-shlibdeps: warning: dependency on libnsl.so.1 [..]"

- Solaris needs both -lsocket _and_ -lnsl
- A/UX needs -lUTIL

"... which totally sucks because we'd link libnsl on Linux, too
(where its not needed at all). So, we have to figure out how to tell
autocrap to NOT put -lnsl there unless it exports a symbol we need.
This also means that [...] has to be reverted (or done properly)."
					-- Florian Westphal @ #ngircd

This reverts commit 2b14234abc252383679bae2d23861b773dc9713e.