Change recommended startup timing

Extend recommended  delay from start of snmpd to start of
pn_dev application.
This fixes an issue seen while running the ART Topology test
where SNMP requests failed because the pn_dev snmpd
integration had not been started.

Author: olbjo

doc/additional_linux_details.rst

@@ -230,7 +230,7 @@ the ``[Unit]`` part of your ``.service`` file::
 You might also need to add this to the ``[Service]`` part of your
 ``.service`` file::
 
-   ExecStartPre=/usr/bin/sleep 0.3
+   ExecStartPre=/usr/bin/sleep 1.0
 
 If the P-Net application fails to connect to snmpd, a message "Warning: Failed
 to connect to the agentx master agent" will be written to the P-Net sample

src/ports/linux/pnet-sampleapp.service

@@ -13,7 +13,7 @@ ExecStartPre=/sbin/ifconfig eth0 up
 ExecStartPre=/bin/sh -c '/bin/echo "49152 60999" > /proc/sys/net/ipv4/ip_local_port_range'
 ExecStartPre=/usr/bin/enable-rpi-gpio-pins.sh
 # Enable this line if waiting for snmpd to start
-#ExecStartPre=/usr/bin/sleep 0.3
+#ExecStartPre=/usr/bin/sleep 1.0
 WorkingDirectory=/home/pi/profinet/build/
 ExecStart=/home/pi/profinet/build/pn_dev -v -b /sys/class/gpio/gpio27/value -d /sys/class/gpio/gpio22/value
 # Use this instead for dual ports: