package/tftpd: add include of config file to init script

HPA's tftp server init script does not support include of a
configuration file. So changing daemon parameters would cause
a modification of the init script.
Similar to NFS, dropbear, DHCP, SNMP and other network services
in buildroot, this patch adds an include of /etc/default/tftpd
to the init script. So any user can change the default behaviour
by adding its own configuration file instead of changing the init
script.

Signed-off-by: Andreas Ehmanns <universeiii@gmx.de>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 61bfaf0354)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/tftpd/S80tftpd-hpa

@@ -11,6 +11,8 @@ DAEMON=/usr/sbin/$NAME
 PIDFILE=/var/run/$NAME.pid
 SCRIPTNAME=/etc/init.d/S80tftpd-hpa
 
+[ -r "/etc/default/$NAME" ] && . "/etc/default/$NAME"
+
 #
 #	Function that starts the daemon/service.
 #