rp-pppoe-server : Startup and configuration items

Maintainer: @cshoredaniel
Environment: arm_arm1176jzf-s_vfp / brcm2708 / bcm2708 (Raspberry Pi B+) w/ OpenWrt 18.06.2

Description:
To allow pppoe-server startup, and also be configurable in OpenWrt GUI, I made the following changes. Please note that I am not sure if this is the best way to fix, but thought providing the following would be helpful:

/etc/init.d/pppoe-server:
In the following line I remove "device" just before "ac_name".
OLD: local enabled interface device ac_name service_names service_name maxsessionsperpeer localip firstremoteip maxsessions optionsfiles randomsession unit offset timeout mss sync OPTIONS
NEW: local enabled interface ac_name service_names service_name maxsessionsperpeer localip firstremoteip maxsessions optionsfiles randomsession unit offset timeout mss sync OPTIONS

I combined the next 2 lines to be one and removed reference to "device" just before the "$interface" reference.
OLD: . /lib/functions/network.sh
network_get_physdev device $interface || return 1
NEW: . /lib/functions/network.sh network_get_physdev $interface || return 1

In the next line I replaced "$device" with "$interface".
OLD: append OPTIONS "-I $device"
NEW: append OPTIONS "-I $interface"

/etc/config/pppoe:
I had to un-comment all the lines so they could be displayed and be managed via the OpenWrt GUI.
Note: Even though I un-commented the pppoe_relay portion of the file, those do not show up however I do not believe I need to use those for just running the PPPoE server (but could be mistaken).

Review /etc/init.d/pppoe-server and /etc/config/pppoe, starting with how the startup script obtains the interface and how configuration entries are exposed to the OpenWrt GUI. Compare the reported old and new forms, then verify that the PPPoE server starts and its settings are manageable in the GUI on the stated OpenWrt environment.