analysis of specifications using Cancelled as an enum value

[cataggar]

This is analysis for https://github.com/Azure/azure-resource-manager-rpc/issues/144 .

[heaths]

I'm not clear on what the intent is, but the Azure guidelines dictate the following values:

• notStarted
• running
• succeeded
• failed
• canceled

Technically, that spec still has them as PascalCase, but more recent conversations have us recommending camelCase for enum values. Whatever the case, the public API would be using snake_case anyway, but we should probably handle these values case-insensitively as well as "cancelled" == "canceled" like we do in other languages.

I'll ping @JeffreyRichter and others offline about the casing of these values as we recommended them here, but the case-insensitive text is still correct.

[cataggar]

I used this example to locate the 8 services that are using Cancelled in provisioningState, when they should be using Canceled. This includes the vmware service, which I manage. I still think this example is worth merging. It shows how to loop through the models for analysis.