QQuickImageProvider does not always preserve id

For example, using the texture provider at examples/quick/textureprovider/ with the following code:

Image {
    source: "image://etc/../images/myImage.pkm"
}

Will call requestTexture with an id of "images/myImage.pkm" (the "../" has been lost). Changing this code to:

property string path: "image://etc/../images/myImage.pkm"
source: path

Will correctly call requestTexture with an id of "../images/myImage.pkm".