Do not close changeset after "cancelled upload"

[chriscf]

A transient fault in the connection can result in a CancelledUploadException, which leaves the upload incomplete, and if marked for closure the changeset is closed. In such a situation, it probably shouldn't be closed until the upload completes successfully.

POST http://www.openstreetmap.org/api/0.6/changeset/xxxxxxx/upload... Proxy Error
Waiting 10 seconds ... org.openstreetmap.josm.io.OsmTransferCancelledException
        at org.openstreetmap.josm.io.OsmApi.sleepAndListen(OsmApi.java:484)
        at org.openstreetmap.josm.io.OsmApi.sendRequest(OsmApi.java:569)
        at org.openstreetmap.josm.io.OsmApi.sendRequest(OsmApi.java:508)
        at org.openstreetmap.josm.io.OsmApi.uploadDiff(OsmApi.java:458)
        at org.openstreetmap.josm.io.OsmServerWriter.uploadChangesInChunks(OsmServerWriter.java:163)
        at org.openstreetmap.josm.io.OsmServerWriter.uploadOsm(OsmServerWriter.java:205)
        at org.openstreetmap.josm.gui.io.UploadPrimitivesTask.realRun(UploadPrimitivesTask.java:236)
        at org.openstreetmap.josm.gui.PleaseWaitRunnable.doRealRun(PleaseWaitRunnable.java:83)
        at org.openstreetmap.josm.gui.PleaseWaitRunnable.run(PleaseWaitRunnable.java:129)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)
PUT http://www.openstreetmap.org/api/0.6/changeset/7529595/close... OK