[RFC PATCH 4.4] Documentation/network: reword kernel version reference

[Mark Rustad <mrustad@gmail.com>]

It seemed odd to say "since 4.17" in a 4.4 kernel. Consider
rewording the reference to indicate where in the stable series
it was introduced as well as where it originated.

Signed-off-by: Mark Rustad <mrustad@gmail.com>

---

Does this brief elaboration add useful information? It seems to
me that someone using a particular series of stable kernels would
find this information to be helpful or at least potentially less
confusing to a non-developer.
---
 Documentation/networking/ip-sysctl.txt |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 7c229f59016f..2fb35658d151 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -116,7 +116,7 @@ ipfrag_high_thresh - LONG INTEGER
 	Maximum memory used to reassemble IP fragments.
 
 ipfrag_low_thresh - LONG INTEGER
-	(Obsolete since linux-4.17)
+	(Obsolete since linux-4.4.174, backported from linux-4.17)
 	Maximum memory used to reassemble IP fragments before the kernel
 	begins to remove incomplete fragment queues to free up resources.
 	The kernel still accepts new fragments for defragmentation.