Bump to AHC 1.19.40 to support better SSL defaults

AHC < 1.19.31 allows connection with SSLv2 and SSLv3. This removes support for those insecure
protocols by default.

Author: farmdawgnation

core/build.sbt

@@ -4,7 +4,7 @@ description :=
   "Core Dispatch module wrapping sonatype/async-http-client"
 
 libraryDependencies +=
-  "com.ning" % "async-http-client" % "1.9.11"
+  "com.ning" % "async-http-client" % "1.9.40"
 
 Seq(lsSettings :_*)