QtKitInformation: Also show invalid Qt versions in the config widget

They are used, so show them.

Change-Id: I28f7dca3d2597c5d9bd43dbc07ba59ebc6309606
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
QtVersion: Do not consider a valid Qt equal to an invalid Qt

Otherwise there is no changed signal once a Qt version becomes valid
which is required to e.g. re-check the validity of the kits that use
this Qt version.

Task-number: QTCREATORBUG-10222
Change-Id: I117fc08bd8ef775c50df654d760e4540e07e6c61
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
QtKitInformation: Recheck validiy of kits on Qt version changes

Task-number: QTCREATORBUG-10222

Change-Id: I9cdd86c103631f0b6a0362437ccedac222ab22c3
Reviewed-by: Daniel Teske <daniel.teske@digia.com>