DOC: lua: update a few doc URLs

The HAProxy doc was updated to point to docs.haproxy.org.
The HAProxy API doc was returning a 404, let's point to version 2.6.
This should be backported with 1.9dev modified to match the respective
versions.

(cherry picked from commit 77ec4626704e15461c58e32b26cb4c2adc6f50ce)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 0e73b7b9ed624fffae2bb349c8dd7aa3bc49fbab)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/doc/lua.txt b/doc/lua.txt
index 4a63e57..289bd18 100644
--- a/doc/lua.txt
+++ b/doc/lua.txt
@@ -83,9 +83,9 @@
 Reading the following documentation links is required to understand the
 current paragraph:
 
-   HAProxy doc: http://cbonte.github.io/haproxy-dconv/
+   HAProxy doc: http://docs.haproxy.org/
    Lua API:     http://www.lua.org/manual/5.3/
-   HAProxy API: http://www.arpalert.org/src/haproxy-lua-api/1.9dev/index.html
+   HAProxy API: http://www.arpalert.org/src/haproxy-lua-api/2.6/index.html
    Lua guide:   http://www.lua.org/pil/
 
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