container: wrap container init start errors

This helps indicate the exact origin and nature of the error. This eliminates generic WrapErr from container.

Signed-off-by: Ophestra <cat@gensokyo.uk>

system/output.go

@@ -33,14 +33,16 @@ func (e *OpError) Error() string {
 	}
 
 	switch {
-	case errors.As(e.Err, new(*os.PathError)), errors.As(e.Err, new(*net.OpError)):
+	case errors.As(e.Err, new(*os.PathError)),
+		errors.As(e.Err, new(*net.OpError)),
+		errors.As(e.Err, new(*container.StartError)):
 		return e.Err.Error()
 
 	default:
 		if !e.Revert {
-			return "cannot apply " + e.Op + ": " + e.Err.Error()
+			return "apply " + e.Op + ": " + e.Err.Error()
 		} else {
-			return "cannot revert " + e.Op + ": " + e.Err.Error()
+			return "revert " + e.Op + ": " + e.Err.Error()
 		}
 	}
 }

system/output_test.go

@@ -26,11 +26,11 @@ func TestOpError(t *testing.T) {
 			ErrDBusConfig, syscall.ENOTRECOVERABLE},
 
 		{"apply", newOpError("tmpfile", syscall.EBADE, false),
-			"cannot apply tmpfile: invalid exchange",
+			"apply tmpfile: invalid exchange",
 			syscall.EBADE, syscall.EBADF},
 
 		{"revert", newOpError("wayland", syscall.EBADF, true),
-			"cannot revert wayland: bad file descriptor",
+			"revert wayland: bad file descriptor",
 			syscall.EBADF, syscall.EBADE},
 
 		{"path", newOpError("tmpfile", &os.PathError{Op: "stat", Path: "/run/dbus", Err: syscall.EISDIR}, false),