Populate default values before echoing help text

Testing showed that it may take a few seconds for the default values to
populate.  If the help text is shown, “Enter the public IP address…,”
but no prompt is shown, the user may get confused and try to enter the
IP address before mailinabox has had a chance to figure out and display
a suitable default value.

setup/start.sh

@@ -24,6 +24,11 @@ fi
 # Gather information from the user about the hostname and public IP
 # address of this host.
 if [ -z "$PUBLIC_HOSTNAME" ]; then
+	if [ -z "$DEFAULT_PUBLIC_HOSTNAME" ]; then
+		# set a default on first run
+		DEFAULT_PUBLIC_HOSTNAME=`get_default_hostname`
+	fi
+
 	echo
 	echo "Enter the hostname you want to assign to this machine."
 	echo "We've guessed a value. Just backspace it if it's wrong."
@@ -31,39 +36,34 @@ if [ -z "$PUBLIC_HOSTNAME" ]; then
 	echo "be similar."
 	echo
 
-	if [ -z "$DEFAULT_PUBLIC_HOSTNAME" ]; then
-		# set a default on first run
-		DEFAULT_PUBLIC_HOSTNAME=`get_default_hostname`
-	fi
-
 	read -e -i "$DEFAULT_PUBLIC_HOSTNAME" -p "Hostname: " PUBLIC_HOSTNAME
 fi
 
 if [ -z "$PUBLIC_IP" ]; then
+	if [ -z "$DEFAULT_PUBLIC_IP" ]; then
+		# set a default on first run
+		DEFAULT_PUBLIC_IP=`get_default_publicip`
+	fi
+
 	echo
 	echo "Enter the public IP address of this machine, as given to"
 	echo "you by your ISP. We've guessed a value, but just backspace"
 	echo "it if it's wrong."
 	echo
 
-	if [ -z "$DEFAULT_PUBLIC_IP" ]; then
-		# set a default on first run
-		DEFAULT_PUBLIC_IP=`get_default_publicip`
-	fi
-
 	read -e -i "$DEFAULT_PUBLIC_IP" -p "Public IP: " PUBLIC_IP
 fi
 
 if [ -z "$PUBLIC_IPV6" ]; then
-	echo
-	echo "(Optional) Enter the IPv6 address of this machine. Leave blank"
-	echo "           if the machine does not have an IPv6 address."
-
-	if [ -z "$DEFAULT_PUBLIC_IPV6" ]; then 
+	if [ -z "$DEFAULT_PUBLIC_IPV6" ]; then
 		# set a default on first run
 		DEFAULT_PUBLIC_IPV6=`get_default_publicipv6`
 	fi
 
+	echo
+	echo "(Optional) Enter the IPv6 address of this machine. Leave blank"
+	echo "           if the machine does not have an IPv6 address."
+
 	read -e -i "$DEFAULT_PUBLIC_IPV6" -p "Public IPv6: " PUBLIC_IPV6
 fi