Change fileclient from urllib2 to requests

[techhat]

This makes requests a hard dependency for Salt.

This should only be merged by @thatch45.

@basepi, please do not cherry pick.

[ghost]

Test Failed.

If the failures are unrelated to your code, don't stress, a core developer will know these apart.
In the future, if possible, please branch off a passing commit to avoid false positives.
Refer to this link for build results: http://jenkins.saltstack.com/job/salt-pr-build/2970/