Official Canadian source saying bitcoin is not legal tender?
The Currency Act defines what is meant by legal tender in Canada:


Legal tender

8. (1) Subject to this section, a tender of payment of money is a legal tender if it is made
(a) in coins that are current under section 7; and
(b) in notes issued by the Bank of Canada pursuant to the Bank of Canada Act intended for 
circulation in Canada.


Since these are the only two forms of payment considered legal tender, and bitcoins are quite clearly neither of these, the conclusion must be that bitcoins are not legal tender in Canada. Note that the Act doesn't explicitly have to name Bitcoin for this conclusion to nevertheless be true.