Those clauses were quite common years ago. When I helped my parents sell their house in the suburbs of Philadelphia in the late 70s, I (and they) were surprised to see such a clause in their deed. I wondered what the title company would do with it, particularly since the couple buying their house was Black. When I got the title report there was a simple notation to the effect that the clause (referenced only by number) was no longer legally enforceable.
The restrictive covenant thing was essentially meaningless anyway, because the Supreme Court had already ruled in 1948 that government enforcement of racially restrictive covenants is unconstitutional.
See http://en.wikipedia.org/wiki/Shelley_v._Kraemer