CI: Unbreak gofmt logic
CI: Unbreak gofmt logic

The script ".ci/go-static-checks.sh" was trying to exclude all vendor
files and files below pause/. However, the logic was incorrect meaning
the only file actually being gofmt-checked was pause.go!

Since the pause binary is now written in go [1], in fact we only want
to exclude "vendor/*" files.

---
[1] - https://github.com/clearcontainers/runtime/pull/434

Fixes #624.

Signed-off-by: James O. D. Hunt <348fbaadfbada55ea105602bf5609e23ac1c4898@intel.com>

chavafg/runtime,clearcontainers/runtime,chavafg/runtime,devimc/runtime,clearcontainers/runtime,devimc/runtime