ahc-default.properties causes conflicts in shading

[wsargent]

Play-WS will shade AHC's version of Netty to ensure that other Netty libraries can be used i.e. Netty 3.x can be used with AHC Netty 4.x.

However, AHC points to /ahc-default.properties, which is hardcoded to point to the root resource. This has caused issues when people include libraries that depend on older versions of AHC, such as Dispatch or Cassandra.

playframework/play-ws#229

The ideal solution would be for AHC to do some introspection on the package and call up the current package, and then refer to <package-name>/ahc-defaults.properties -- that way it would be guaranteed local to whereever it was shaded.

[slandelle]

PR? ;-)

[wsargent]

@slandelle done

[wsargent]

One thing to note -- I don't know how this is affected in OSGi environments, i.e. #1345 -- maybe @isopov can review?