Fixes #6944/bz1106434 - Fixed Repodiscovery product validation

Added code in the repo discovery page to validate new product.
Previously product errors like blank name invalid label etc would not
show up on the screen. This commit tries to address that.
We typically align this as:

```
   <select ng-model="createRepoChoices.product.gpg_key_id"
               ng-options="gpg_key.id as gpg_key.name for gpg_key in gpgKeys">
   </select>
```