ReportData - change long_id to string

[himdel]

long_id in report data comes from the @record.id field - but Ruby ints can be bigger than JS ints => we
need a string so that it's not bigger than INT_MAX in JS, for large region numbers.

Cc @karelhala

[himdel]

(gaprindashvili/yes - most likely needed by #2791)

[himdel]

(Note to self: #2842 introduces 2 more tests that need a to_s)

[miq-bot]

Checked commit https://github.com/himdel/manageiq-ui-classic/commit/716037a305eb462f5ee6a6ae4caadd593f7ee015 with ruby 2.3.3, rubocop 0.47.1, haml-lint 0.20.0, and yamllint 1.10.0
2 files checked, 0 offenses detected
Everything looks fine. 🍰

[simaishi]

Gaprindashvili backport details:

$ git log -1
commit d63d0f11e7544962c5f987e830327c83d5d1cc6a
Author: Milan Zázrivec <mzazrivec@redhat.com>
Date:   Mon Dec 4 09:00:23 2017 +0100

    Merge pull request #2902 from himdel/str-long-i
    
    ReportData - change long_id to string
    (cherry picked from commit 59164c296d8b757aaf4c8e98fc61ff946649874c)

[himdel]

issue: #1405

[JPrause]

@miq-bot add_label blocker