Merge "timeout" pull request

[guruz]

Hi, We had experienced hanging sockets to the Amazon servers when using the Product Advertising API. This led to our application being deadlocked as soon as 5 sockets were hanging (5 is the default number of sockets for node's https agent).

When using lsof you could see it like this:

node      20371       user   11u     IPv4         abc        0t0        TCP xxxx:49297->72.21.215.235:https (ESTABLISHED)
node      20371       user   12u     IPv4         cde        0t0        TCP xxxx:45374->72.21.215.235:https (ESTABLISHED)
...

Using a fork with the https://github.com/casualsteps/aws-lib/pull/1 pull request and setting the timeout to 10 seconds fixed the issue for us.

Would be nice to see this in the main codebase.

CC @kenleytomlin @ogoffart @jturcotte