South African President Cyril Ramaphosa has appointed veteran politician Roelf Meyer as the country's ambassador to the United States , after a year when the post was vacant amid difficult ties with Donald Trump 's administration in Washington.  Ramaphosa's spokesman Vicent Magwenya announced the appointment in a message to the Associated Press and other news outlets.  "I can confirm that President Cyril Ramaphosa has appointed Mr. Roelf Meyer as South Africa 's Ambassador to the US," he said, effective immediately.  Who is Roelf Meyer?  Roelf Meyer was a member of parliament from 1979 to 1997 and was minister of defense from 1991 to 1992 under the white minority government of former President F.W.…