Domain wizard: If domain creation fails because of name that's already used (or forbidden), no info is visible in wizard after you closed the error dialog

If you create a new domain on OpenShift, you'll have to provide it's name. This name has to be unique across OpenShift (for all users). If you use a domain name that's already used, you'll get an error dialog that informs you about the name not being unique across OpenShift.

Once you close this dialog, noting is showing this error any more. The name field is not decorated with an error marker.

steps to reproduce:

1. ASSERT make sure you have an account without a domain
2. EXEC launch the OpenShift Application wizard
3. ASSERT you get to the Domain creation dialog
4. EXEC supply a valid key and choose a domain name that is already used (ex. "domain")
5. ASSERT You get an error dialog that tells you that the domain name is already used
6. EXEC hit OK

Result:
The domain creation dialog has no information that would tell you what you have to correct.

We should improved this:

• put an error decoration to the name text field
• put the cursor into the name text field (eventually select the whole name in it)
• eventually reach out to #libra to get a way to query the availability of the given name, so that we can validate while typing.