RouteController: use fixed priority for ip rule

Use fixed priority when adding source policy rules

CR-fixed: 613222
Change-Id: I3182777db6b665c6adc94f65e91b429aac733875
PPPOE: Add PPPOE support

Add PPPOE support, include kernel and frameworks:
    1. Enable PPP&PPPoE Module in Linux Kernel
    2. Obtain the PPPoE Dialing Program with rp-pppoe-3.10
    3. Add pppoe command listenner to handle pppoe dial command
    4. Add PPPOESearvice to send pppoe command
    5. Add pppoe_enable system property.
    6. Support 3 interface for app start/stop pppoe getpppoeinfo
    7. Send broadcast when pppoe connnecting/connnected/disconnnect
    8. Send broadcast that if app called start pppoe success

CRs-Fixed: 501396

Change-Id: I8d3c44c7f5796f6b81768961a099d8a4b4ae53fc

Conflicts:
	CommandListener.cpp
Merge "PPPOE: Add PPPOE support"
Merge "RouteController: use fixed priority for ip rule"
netd: Use append to add routes to secondary routing table

Use <ip route append> instead of <ip route add>
to add routes to the secondary routing table. This
is because adding a route with same v6 address but
different device name fails by using <ip route add>

CRs-Fixed: 618837
Change-Id: Id880e1a155856a5a3afad75135091a17ace07414
Merge "netd: Use append to add routes to secondary routing table"
Netd: Do not reset routing policies

Stop flushing of all routing policies when resetting to default rule
configuration. This is detrimental to other policy routes set on the
system and creates a conflict. Tethering related rules are already
removed by NatController so this step is unnecessary.

Change-Id: Id9026c089262e37fffe6e5db8eb8e0ccf3338c94
PPPOE: Fix pppoe can't connect to Internet issue

1.DUT can not access Internet if adding interface for
default route only. Set gateway for default route also.

2.The path of pppoe binary is not correct, correct the
path. And it can't stop pppoe process if killing
the pppd process only.  Also kill pppoe process when
stopping pppoe.

Change-Id: I24c1a375366ff9784e8b5059309f492e548bca2e
Merge "PPPOE: Fix pppoe can't connect to Internet issue"
Merge "Netd: Do not reset routing policies"