When the client reads DH parameters from the TLS stream, we only
checked that they all are non-zero. This change updates the check to
use DH_check_params()
DH_check_params() is a new function for light weight checking of the p
and g parameters:
check that p is odd
check that 1 < g < p - 1
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
a39aa18644