Comment 16 for bug 1633387

Reviewed: https://review.opencontrail.org/41434
Committed: http://github.com/Juniper/contrail-vrouter/commit/1dacc5c15788bce3b8f889e7ecbf256d4b661e49
Submitter: Zuul (<email address hidden>)
Branch: R4.1

commit 1dacc5c15788bce3b8f889e7ecbf256d4b661e49
Author: Antoine Eiche <email address hidden>
Date: Tue Dec 5 17:31:03 2017 +0100

Fix build for kernels >= 4.9

- skb_sender_cpu_clear has been removed in kernel 4.6 [1] and is no longer
required since 4.5 [2].

- get_user_page signature has changed in 4.6 [3] and in 4.9 [4]. Since I
don't have a 4.6 kernel for testing, I didn't add code to support it.

- The macro page_cache_release has been finally removed [5].

[1] https://github.com/torvalds/linux/commit/64d4e3431e686dc37ce388ba531c4c4e866fb141
[2] https://github.com/torvalds/linux/commit/52bd2d62ce6758d811edcbd2256eb9ea7f6a56cb
[3] https://github.com/torvalds/linux/commit/c12d2da56d0e07d230968ee2305aaa86b93a6832
[4] https://github.com/torvalds/linux/commit/768ae309a96103ed02eb1e111e838c87854d8b51
[5] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=09cbfeaf1a5a67bfb3201e0c83c810cecb2efa5a

Change-Id: I569ca66145204f6e71a1083412bf2cb4caab818d
Partial-Bug: #1633387
(cherry picked from commit a0d6eb08e9acb55f000a666b21ad6324fe50acc9)