platform/api/azure: cleanup after Azcopy

Azcopy unfortunately leaves behind log files and plan files in $HOME/.azcopy.
Passing `--log-level=NONE` removes the log files (but stdout remains informational)
and the plans files are cleaned up after the copy command finishes.

Signed-off-by: Jeremi Piotrowski <jpiotrowski@microsoft.com>

platform/api/azure/storage_mit.go

@@ -352,10 +352,12 @@ func (a *API) CopyBlob(storageaccount, storagekey, container, targetBlob, source
 		if err != nil {
 			return err
 		}
-		cmd := exec.Command(azcopy, "cp", "--blob-type=PageBlob", sourceBlob, dstSas)
+		cmd := exec.Command(azcopy, "cp", "--blob-type=PageBlob", "--log-level=NONE", sourceBlob, dstSas)
 		cmd.Stderr = os.Stderr
 		cmd.Stdout = os.Stdout
 		err = cmd.Run()
+		// azcopy leaves behind "plan" files in case a job needs to be retried
+		_ = exec.Command("azcopy", "jobs", "clean").Run()
 		if err == nil {
 			return nil
 		}