Made the IPv6 option in the final DNS records output optional depending on the v6choice variable defined by the user

emailwiz.sh

@@ -365,7 +365,7 @@ done
 pval="$(tr -d '\n' <"/etc/postfix/dkim/$domain/$subdom.txt" | sed "s/k=rsa.* \"p=/k=rsa; p=/;s/\"\s*\"//;s/\"\s*).*//" | grep -o 'p=.*')"
 dkimentry="$subdom._domainkey.$domain	TXT	v=DKIM1; k=rsa; $pval"
 dmarcentry="_dmarc.$domain	TXT	v=DMARC1; p=reject; rua=mailto:postmaster@$domain; fo=1"
-spfentry="$domain	TXT	v=spf1 mx a:$maildomain ip4:$ipv4 ip6:$ipv6 -all"
+spfentry="$domain	TXT	v=spf1 mx a:$maildomain ip4:$ipv4 $( [ "${v6choice#n}" ] && printf 'ip6:%s' "$ipv6" ) -all"
 mxentry="$domain	MX	10	$maildomain	300"
 
 useradd -m -G mail postmaster