uuid: fix comments
uuid: fix comments

R=ajrisi
CC=borman
http://codereview.appspot.com/4819072

yxd-hde/uuid,E-B-Smith/uuid,Xe/uuid,jboverfelt/uuid,wallclockbuilder/uuid,google/uuid,odeke-em/go-uuid,mjgarton/uuid,pborman/uuid,zemirco/uuid