Make use of standard variables for installation

otherwise %cmake rpm macros will not be able to install things to
the right places.

Author: watologo1

CMakeLists.txt

@@ -96,10 +96,10 @@ if(CZMQ_FOUND)
 endif()
 
 install(TARGETS redfishtest redfish
-        RUNTIME DESTINATION bin
-        LIBRARY DESTINATION lib)
-install(FILES ${REDFISH_HDR_PUBLIC_RED} DESTINATION include)
-install(FILES ${REDFISH_HDR_PUBLIC_ENTITIES} DESTINATION include/entities)
+        RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
+        LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}")
+install(FILES ${REDFISH_HDR_PUBLIC_RED} DESTINATION "${INCLUDE_INSTALL_DIR}")
+install(FILES ${REDFISH_HDR_PUBLIC_ENTITIES} DESTINATION "${INCLUDE_INSTALL_DIR}/entities")
 
 ENABLE_TESTING()