Unwind the exception causes with Java11Http#performConnect

Currently there is a generic exception caught for all kind of errors but
as the execution is actually performed async this means that any
exception is already wrapped in an ExecutionException holding the real
cause.

This unwinds the different causes that an happen (e.g. cancel, timeout,
...) and finally checks if this is an ExecutionException from the async
operation-

providers/bundles/org.eclipse.ecf.provider.filetransfer.httpclientjava/src/org/eclipse/ecf/provider/filetransfer/httpclientjava/HttpClientRetrieveFileTransfer.java

@@ -36,7 +36,9 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.CancellationException;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.zip.GZIPInputStream;
 
@@ -1006,11 +1008,26 @@ private IStatus performConnect(IProgressMonitor monitor) {
 		int ticks = 1;
 		monitor.beginTask(getRemoteFileURL().toString() + Messages.HttpClientRetrieveFileTransfer_CONNECTING_TASK_NAME, ticks);
 		try {
-			if (monitor.isCanceled())
-				throw newUserCancelledException();
+			if (monitor.isCanceled()) {
+				setDoneCanceled();
+				return Status.CANCEL_STATUS;
+			}
 			httpResponse = httpClient.sendAsync(httpRequest, BodyHandlers.ofInputStream());
 			responseCode = httpResponse.get(getConnectTimeout(),TimeUnit.MILLISECONDS).statusCode();
-		} catch (final Exception e) {
+		} catch (InterruptedException e) {
+			Thread.currentThread().interrupt();
+			setDoneCanceled();
+			return Status.CANCEL_STATUS;
+		} catch (CancellationException e) {
+			setDoneCanceled();
+			return Status.CANCEL_STATUS;
+		} catch (Exception e) {
+			if (e instanceof ExecutionException) {
+				Throwable cause = ((ExecutionException) e).getCause();
+				if (cause instanceof Exception) {
+					e = (Exception) cause;
+				}
+			}
 			Trace.catching(Activator.PLUGIN_ID, DebugOptions.EXCEPTIONS_CATCHING, this.getClass(), "performConnect", e); //$NON-NLS-1$
 			if (!isDone()) {
 				setDoneException(e);