CP-4959: EA-1246: If RPUW cancelled, inform users about restarting it.

New info dialog displayed when the user cancels the last page (Apply Upgrade page) of the Rolling Pool Upgrade wizard.

Signed-off-by: Adrian Jachacy <Adrian.Jachacy@citrix.com>
CP-4959: EA-1246: If RPUW cancelled, inform users about restarting it.

Minor code refactoring to address the comment raised in review #2003.

Signed-off-by: Adrian Jachacy <Adrian.Jachacy@citrix.com>