Oil prices rose slightly on Friday before a long holiday weekend in the US as wary optimism held over efforts to make peace in the Middle East between the United States and Iran. Brent futures were up 17 cents, or 0.24%, to $72.10 a barrel as of 0155 GMT. West Texas Intermediate was up 14 cents, or 0.20%, to $68.83 a barrel. US markets will close on Friday ahead of the US Independence