rhbz903964 - produce better error message when permission check failed

[huangp]

https://bugzilla.redhat.com/show_bug.cgi?id=903964

For example, when invoke client with following command:
z -B push --push-type trans --merge-type import

There are two(maybe more) possible permission failure:

• user is not part of the language team
• user don't have permission to do merge type import operation

In the past what we get back is just a 401 with no body in response. Now we can tell what exactly go wrong:

• when user is not a member for the locale

[ERROR] Execution failed: 
 * Error Message: PUT http://localhost:8080/zanata/rest/async/projects/p/jasper/iterations/i/1/r/MessageResources/translations/de?ext=comment&merge=import&assignCreditToUploader=false returned a response status of 401 Unauthorized;
 * Response From Server: Failed to obtain permission(modify-translation) with following facts([Locale(id=de, name=German), Project(name=jasper, slug=jasper, status=ACTIVE)])]

• when user is a translator but not project maintainer (no permission to do merge import)

[ERROR] Execution failed: Failed while pushing document translations: [Failed to obtain permission(import-translation) with following facts([Project version(slug=1, status=ACTIVE)])]

[davidmason]

This is user display name. Username might be more useful to show instead or as well.

[huangp]

username is in HAccount. Although HPerson has fetch=eager annotation on account field, you can always override this. I don't want to cause an extra database call if it's not there.

[davidmason]

👍