image removal: refactor part 2

Continue the refactoring of image removal.  I didn't manage to break all
the following changes into smaller and easier to digest commits due to
time constraints:

 * Return an error slice instead of a single error. Use multierror only
   in the client/frontend.  Reflect that in the types.

 * Use the batch image removal in the client while preserving the more
   rest-idiomatic single-image removal endpoint.

 * Add a new handler for the single-image removal endpoint to make it
   share the same code as the batch endpoint.

 * Expose bindings for the single and batch endpoints, so we can
   properly test them.

 * Add several convenience functions for error handling to
   pkg/errorhandling.

 * Set the correct error type in libpod to set the exit code to 2 when
   one or more containers are using an image.

 * Massage the bindings tests a bit and tackle compilation errors.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/libpod/runtime_img.go b/libpod/runtime_img.go
index 919080c42..cd7f54799 100644
--- a/libpod/runtime_img.go
+++ b/libpod/runtime_img.go
@@ -56,7 +56,7 @@ func (r *Runtime) RemoveImage(ctx context.Context, img *image.Image, force bool)
 				}
 			}
 		} else {
-			return nil, fmt.Errorf("could not remove image %s as it is being used by %d containers", img.ID(), len(imageCtrs))
+			return nil, errors.Wrapf(define.ErrImageInUse, "could not remove image %s as it is being used by %d containers", img.ID(), len(imageCtrs))
 		}
 	}