add entrypoint from image where needed

if the image specifies both the image and entrypoint, we need to account for that and preprend the entrypoint to the command.  this only happens if no user command and entrypoint were supplied.

Signed-off-by: Brent Baude <bbaude@redhat.com>

pkg/specgen/generate/container.go

@@ -13,6 +13,7 @@ import (
 )
 
 func CompleteSpec(ctx context.Context, r *libpod.Runtime, s *specgen.SpecGenerator) error {
+	var appendEntryPoint bool
 
 	newImage, err := r.ImageRuntime().NewFromLocal(s.Image)
 	if err != nil {
@@ -100,6 +101,7 @@ func CompleteSpec(ctx context.Context, r *libpod.Runtime, s *specgen.SpecGenerat
 		return err
 	}
 	if len(s.Entrypoint) < 1 && len(entrypoint) > 0 {
+		appendEntryPoint = true
 		s.Entrypoint = entrypoint
 	}
 	command, err := newImage.Cmd(ctx)
@@ -107,7 +109,10 @@ func CompleteSpec(ctx context.Context, r *libpod.Runtime, s *specgen.SpecGenerat
 		return err
 	}
 	if len(s.Command) < 1 && len(command) > 0 {
-		s.Command = command
+		if appendEntryPoint {
+			s.Command = entrypoint
+		}
+		s.Command = append(s.Command, command...)
 	}
 	if len(s.Command) < 1 && len(s.Entrypoint) < 1 {
 		return errors.Errorf("No command provided or as CMD or ENTRYPOINT in this image")