The INSTALL_NAME_DIR property of a target specifies how a dynamic library should
be found on OS X.  If INSTALL_NAME_DIR is not specified the loader will search
relative to the standard search paths.  If specified it should either be
an absolute path or relative path prefixed with either @executable_path,
@load_path, or @rpath.  Specifying "lib" does not make sense here and
causes linking error as documented here:

http://answers.opencv.org/question/4134/cmake-install_name_tool-absolute-path-for-library-on-mac-osx/

and here

http://stackoverflow.com/questions/26978806/dyld-library-not-loaded-lib-libopencv-core-3-0-dylib-reason-image-not-found

This patch removes INSTALL_NAME_DIR everywhere it is set to "lib".
An alternate solution would be to set an absolute path like
"${CMAKE_INSTALL_PREFIX}/lib" or relative path like
"@executable_path/../lib".  However, if there is not specific need for
specifying a path, it is probably best left unset.