Remove explicit setting of macos install_name

Use CMake default behaviour for libassimp

Fixes #2961

code/CMakeLists.txt

@@ -1213,10 +1213,6 @@ SET_TARGET_PROPERTIES( assimp PROPERTIES
 )
 
 if (APPLE)
-  SET_TARGET_PROPERTIES( assimp PROPERTIES
-    INSTALL_NAME_DIR "${CMAKE_INSTALL_PREFIX}/${ASSIMP_LIB_INSTALL_DIR}"
-  )
-
   if (BUILD_FRAMEWORK)
     SET_TARGET_PROPERTIES( assimp PROPERTIES
       FRAMEWORK TRUE