Validate limit if offset is specified

[jntullo]

Currently if offset is specified and limit is set to 0 (ie limit=0&offset=5), the following error is returned due to division by 0:

{
    "error": {
        "kind": "internal_server_error",
        "message": "Infinity",
        "klass": "FloatDomainError"
    }
}

This updates the LinksBuilder to validate that the limit is greater than 0 if offset is specified.

BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1489885

@miq-bot add_label bug
@miq-bot assign @abellotti

[abellotti]

LGTM!! Thanks @jntullo for the fix. will merge when 🍏

[miq-bot]

Checked commit jntullo@b3f7db5 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
2 files checked, 0 offenses detected
Everything looks fine. 👍