Add DSA support to mkcert.sh

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2667)

test/certs/mkcert.sh

@@ -48,6 +48,7 @@ key() {
         rsa) args=("${args[@]}" -pkeyopt rsa_keygen_bits:$bits );;
         ec)  args=("${args[@]}" -pkeyopt "ec_paramgen_curve:$bits")
                args=("${args[@]}" -pkeyopt ec_param_enc:named_curve);;
+        dsa)  args=(-paramfile "$bits");;
         *) printf "Unsupported key algorithm: %s\n" "$alg" >&2; return 1;;
         esac
         stderr_onerror \