Fix iops values when creating a compute offering

[pbankonier]

Description

When creating a new compute offering over the ui, the isCustomIops parameter is null.
In this case the minIops and maxIops values of the offering gets set to 0 instead of null and when trying to change an instance to this offering an error occurs.
This was introduced in this PR https://github.com/apache/cloudstack/pull/3133/files.
I already opened an issue regarding this. (#3332)

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)

Screenshots:

The marked fields were set to 0 before.

This to screenshots represent the problem.

How Has This Been Tested?

Deployed to local environment and tested functionality.

[svenvogel]

@nathanejohnson can you approve please and check? thanks

UI is important. Cloudmonkey is a great tool but the UI should work and is the first user experience. Its a Regression.

[nathanejohnson]

@svenvogel I will test this locally. thanks for the PR.

[DennisKonrad]

@nathanejohnson I tested this for our use case and the fix is working for us. UI is working just fine. Entries in the database are correct now.

I will wait for the confirmation from your side.

[nathanejohnson]

This same change to the logic would need to be applied down around line 2600

[nathanejohnson]

Ideally I'd still like to get @mike-tutkowski to weigh in here, but as far as I'm concerned LGTM!

[DennisKonrad]

@mike-tutkowski @syed Do you see something more that need to be changed/added to this to restore normal behaviour for managed storage?

We will open a new PR if there's needed more than this small fix @pbankonier

[syed]

LGTM 👍