Fix CMake CMP0042 warning
Fix CMake CMP0042 warning

CMake before 3.0 is very old and can be dropped. @rpath support
was added only in version 2.8.12 and enabled by default in 3.0.
Need to always provide @rpath.

psi-im/jdns,psi-im/jdns,psi-im/jdns