jobsite/manager: create export directory

Be a bit more friendly and actually create the export directory instead
of assuming it exists.

cmd/osbuild-jobsite-manager/main.go

@@ -13,6 +13,7 @@ import (
 	"os"
 	"os/signal"
 	"path"
+	"path/filepath"
 	"syscall"
 	"time"
 
@@ -366,6 +367,16 @@ func StepExport() error {
 				return
 			}
 
+			dstPath := path.Join(argOutputPath, export)
+			dstDir := filepath.Dir(dstPath)
+
+			if _, err := os.Stat(dstDir); os.IsNotExist(err) {
+				logrus.Infof("StepExport: Destination directory does not exist. Creating %s", dstDir)
+				if err := os.MkdirAll(dstDir, 0700); err != nil {
+					errs <- fmt.Errorf("StepExport: Failed to create destination directory: %s", err)
+				}
+			}
+
 			dst, err := os.OpenFile(
 				path.Join(argOutputPath, export),
 				os.O_WRONLY|os.O_CREATE|os.O_EXCL,