frontend: disk dialog - radio button patternfly fix

Disk Dialog:
* Added 'avw_contentWidget_pfly_fix' radio buttons container to
  fix label style.
* Removed redundant 'ui:' prefix for accommodating to uibinder valid syntax.

Change-Id: I5b010807095b5cc8d37c6ed43a05c809cbf8f617
Signed-off-by: Daniel Erez <derez@redhat.com>