BUG/MEDIUM: dns: Don't prevent reading the last byte of the payload in dns_validate_response()

A regression was introduced with efbbdf72 BUG: dns: Prevent out-of-bounds
read in dns_validate_dns_response() as it prevented from taking into account
the last byte of the payload.  this patch aims at fixing it.

this must be backported in 1.8.
1 file changed