Disable IPv6 RS/RA processing in dhcpcd.

Disable IPv6 RS/RA processing in dhcpcd, because:

1. It doesn't make sense to run IPv6 autoconfiguration both in
   the kernel and in dhcpcd.
2. The multinetwork code relies on the kernel IPv6 RS/RA
   implementation, including our patches to put RA-generated
   routes into per-network routing tables, so at best any
   autoconf routes created by dhcpcd will be ignored.
3. dhcpcd SEGVs when receiving certain router advertisements.

3) breaks DHCP renew on Ethernet, because dhcpcd crashes after
receiving an RA, and unlike wifi, the Ethernet code does not do
anything special to renew leases (it just relies on dhcpcd not
crashing). This is obviously a problem on molly.

Bug: 15268738
Change-Id: I05525cd9664ca381657473ac7e20c8ab86cea038
DO NOT MERGE - Disable IPv6 RS/RA processing in dhcpcd.

Disable IPv6 RS/RA processing in dhcpcd, because:

1. It doesn't make sense to run IPv6 autoconfiguration both in
   the kernel and in dhcpcd.
2. The multinetwork code relies on the kernel IPv6 RS/RA
   implementation, including our patches to put RA-generated
   routes into per-network routing tables, so at best any
   autoconf routes created by dhcpcd will be ignored.
3. dhcpcd SEGVs when receiving certain router advertisements.

3) breaks DHCP renew on Ethernet, because dhcpcd crashes after
receiving an RA, and unlike wifi, the Ethernet code does not do
anything special to renew leases (it just relies on dhcpcd not
crashing). This is obviously a problem on molly.

Bug: 15268738
Change-Id: I05525cd9664ca381657473ac7e20c8ab86cea038
(cherry picked from commit 7c5edb63dfd4c6eecbbbba93003ee8c4112b17d0)
am d421bceb: (-s ours) DO NOT MERGE - Disable IPv6 RS/RA processing in dhcpcd.

* commit 'd421bcebbd498a4ef7564924e345e540073c9c77':
  DO NOT MERGE - Disable IPv6 RS/RA processing in dhcpcd.
am 397f843f: Merge "Update compat/closefrom.c to upstream ToT."

* commit '397f843f6c8dc55a48cad015eecbb74f902145b9':
  Update compat/closefrom.c to upstream ToT.
am a02b96d0: Merge "Move dhcpcd off its own getline."

* commit 'a02b96d06acdeb377ffa05525b3b912938fe685c':
  Move dhcpcd off its own getline.
am bea91cfd: Merge "Really disable IPv6 RA processing in dhcpcd."

* commit 'bea91cfdd43d843cdda5ce473d84b7cfcdd566ec':
  Really disable IPv6 RA processing in dhcpcd.
Really disable IPv6 RA processing in dhcpcd.

IPv6 RA processing in dhcpcd causes crashes, so we disabled it in
dhcpcd.conf. Unfortunately devices sometimes don't have the
config file, because one is not required for dhcpcd to work. So
disable IPv6 RA processing in the code too.

(cherry picked from commit 69eb1982f233676775ccb8718fc62e78c137e33d)

Bug: 15268738
Bug: 15779617
Change-Id: I1f8627b9e03abd6487bf6a290feb0578166eb4f0
am 38cb7a7f: Really disable IPv6 RA processing in dhcpcd.

* commit '38cb7a7feff88d58fb4a565ba7f12cd4469af243':
  Really disable IPv6 RA processing in dhcpcd.
am 03baf5ea: Merge "Always include <sys/...>, not <linux/...>."

* commit '03baf5eab896198b5060d287af3fd60d360bf48f':
  Always include <sys/...>, not <linux/...>.
Always include <sys/...>, not <linux/...>.

(cherry picked from commit d9979ed40e2c8d6f9596f0e1e9c64d6b8a0364cc)

Change-Id: I355f4419b4a0cab8ad52ee9a945b56d5236fb668
am 5c826309: Always include <sys/...>, not <linux/...>.

* commit '5c8263095ed5c6f5c08d049f6559abde49658d26':
  Always include <sys/...>, not <linux/...>.
am e8ef8a09: Merge "Suppress warning on comparing array with null."

* commit 'e8ef8a0962dfd5d4cc0c2a45e5ea30042ee11843':
  Suppress warning on comparing array with null.
am 822a5c62: Merge "Fix DoS vulnerability in DHO_OPTIONSOVERLOADED."

* commit '822a5c622d4909cf7aeb618856a05829d865d4a9':
  Fix DoS vulnerability in DHO_OPTIONSOVERLOADED.
am e8960dc7: Merge "Move check of IFF_LOWER_UP after all includes."

* commit 'e8960dc707b76d83fbf8a650314b93d8c28b1a38':
  Move check of IFF_LOWER_UP after all includes.
Fix DoS vulnerability in DHO_OPTIONSOVERLOADED.

Bug: 16677003

(cherry picked from commit 371e319488e62475a4185a93bf47580860268561)

Change-Id: I01446092c7ca9e0133d835cfdae8a9ee467d7aaf
am de806dfd: Fix DoS vulnerability in DHO_OPTIONSOVERLOADED.

* commit 'de806dfdb6dd3b9dec5d1d23c9029fb300799cf8':
  Fix DoS vulnerability in DHO_OPTIONSOVERLOADED.