Replace sudo with su in init script

To avoid issues starting service when 'Defaults requiretty' is enabled in the sudoers file.

Fixes #1204
closes #1205

scripts/init.sh

@@ -138,7 +138,7 @@ case $1 in
         if which start-stop-daemon > /dev/null 2>&1; then
             start-stop-daemon --chuid $USER:$GROUP --start --quiet --pidfile $pidfile --exec $daemon -- -pidfile $pidfile -config $config -config-directory $confdir $TELEGRAF_OPTS >>$STDOUT 2>>$STDERR &
         else
-            nohup sudo -u $USER $daemon -pidfile $pidfile -config $config -config-directory $confdir $TELEGRAF_OPTS >>$STDOUT 2>>$STDERR &
+            su -s /bin/sh -c "nohup $daemon -pidfile $pidfile -config $config -config-directory $confdir $TELEGRAF_OPTS >>$STDOUT 2>>$STDERR &" $USER
         fi
         log_success_msg "$name process was started"
         ;;