Both are acceptable. There was a time, however, when it was recommended that the word none be followed by a singular verb. But times have changed. It is now possible to use either a singular or a plural verb when none refers to a countable noun.
For example it is possible to say:
• None of the telephones is/are working.
• None of the students have/has turned up.
• None of the children is/are happy.
People who are extremely fond of grammar insist, even today, that a singular and not a plural verb should follow none.
COURTESY : The Hindu (The National News-Paper) - India