overstate: Patching to fail on requisite failures.

This patch fixes #7563 and #5313.  I wouldn't suggest merging it without testing but I'm submitting a pull request so that people can use this if they need overstates before the next release.

Basically I moved the check results function out of line with the call_stage function and called it again after running any child requisites.

Download the patch here: https://github.com/saltstack/salt/pull/7675.patch