BaseQtVersion: Make qmakeProperty(versionInfo, name, ...) protected

This is a low level method which is not useful for normal usage.

Change-Id: I5fd1c019856a8a84299f5b11c159ea6b0f5131a9
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
BaseQtVersion: Make sure qmake variables are up to date.

Otherwise, qmake properties can be wrongly read as empty.

Change-Id: If63a306664758c01529b437fca30f5222b75f02f
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
DebuggerKitInformation: Invalid ids are ok

Invalid Ids are used to for "No Debugger", so do not try to fix
those values.

Change-Id: I141f969524e1faffa66a22c2a08ef18ec4d7fc23
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
DebuggerKitInformation: Make setup() handle new kits

Those return a invalid QVariant, so handle that explicitly.

Change-Id: I50726552aeb76d21032c119c5ea2db48e6d88e8b
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>