Merge pull request airbnb#170 from hightoxicity/feat-ha1.6-http-reuse

Be able to use http-reuse to make connections pooling with backends

Author: jolynch

lib/synapse/haproxy.rb

@@ -37,6 +37,7 @@ class Haproxy
         "http-check send-state",
         "http-request",
         "http-response",
+        "http-reuse",
         "id",
         "ignore-persist",
         "log",
@@ -166,6 +167,7 @@ class Haproxy
         "hash-type",
         "http-check disable-on-404",
         "http-check send-state",
+        "http-reuse",
         "log",
         "maxconn",
         "mode",
@@ -377,6 +379,7 @@ class Haproxy
         "http-check send-state",
         "http-request",
         "http-response",
+        "http-reuse",
         "id",
         "ignore-persist",
         "log",