qmlplugindump: set isCreatable true in composite types
qmlplugindump: set isCreatable true in composite types

the qmlengine defines isCreatable as "is creatable through the C++
interface", for the qmltypes and qml code model it makes sense to
define isCreatable as "can appear as component in QML"

Change-Id: Ib26cf25dd5a70e1c03ce017e8ae572e8a9e562c1
Reviewed-by: Jens Bache-Wiig <9cea9d70b08f8210134ec5959114f72bad51ed1d@digia.com>
Reviewed-by: Kai Koehne <077bc265216106fb22408e62f2d97925ede69d10@digia.com>
Reviewed-by: Thomas Hartmann <588ee739c05aab7547907becfd1420d2b7316069@digia.com>

mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative