Only accept auth=qop for digest authentication

Since we implement the digest authentication process and require
auth=qop in our authorization request from the client, a valid
response must include auth=qop as well.

Change-Id: I2ecd4bc8568ad432ac7f54d82e465be06dc01993
Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed