CI: re-enable TODO/FIXME checker

[jodh-intel]

Our CI tests have a check that will fail a PR if if changes any files that contain TODO or FIXME comments. We have this since such comments tends to never get fixed. As such, it is much better to have a reference to a github issue for the problem as that makes it visible.

The checker was added on PR #445 but had to be disabled with PR #464 as it was causing the CI builds to fail.

Once the following issues have been closed, this issue can be used to re-enable the TODO/FIXME checker:

• Add issue URL to "bare" TODO/FIXME comments agent#287
• Add issue URL to "bare" TODO/FIXME comments ci#45
• Add issue URL to "bare" TODO/FIXME comments packaging#84
• Add issue URL to "bare" TODO/FIXME comments runtime#459
• Add issue URL to "bare" TODO/FIXME comments #468

[jodh-intel]

When #471 lands, it will be possible to run just check TODO/FIXME checker on a repo like this:

$ export KATA_DEV_MODE=true
$ $GOPATH/src/github.com/kata-containers/tests/.ci/static-checks.sh --master --files --force

[jodh-intel]

The command should (now) actually be:

$ $GOPATH/src/github.com/kata-containers/tests/.ci/static-checks.sh --files --force --all

(but blocked by #999).