Fix undeclared std::function on gcc 7.1
Fix undeclared std::function on gcc 7.1

Resolves: LE-7179
Change-Id: I6ca67e3f12de0ffdc265c0086203b920f9e9f188

legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af