Make our life easier when passing an exit code and message to `SaltSyetemExit`.
Minor formating changes.
Don't just exit! Allow the exit to be catch and be handled on the CLI code.
Handle DNS check issues. Fixes #4988. Refs saltstack/salt-bootstrap#122.
Catch more socket errors. Fixes saltstack/salt-bootstrap#122
Complete the fix for #4980 started in 31b2574194d5333c65aec34c916609bad4b9490d

* Minor PEP8 and formatting changes.
Merge pull request #4997 from s0undt3ch/develop

Improved handling of dns_check