core: don't mount kdbusfs if not wanted

Just like we conditionalize loading kdbus.ko, we should conditionalize
mounting kdbusfs. Otherwise, we might run with kdbus if it is builtin,
even though the user didn't want this.

src/core/mount-setup.c

@@ -105,7 +105,7 @@ static const MountPoint mount_table[] = {
           is_efi_boot,   MNT_NONE                   },
 #endif
         { "kdbusfs",    "/sys/fs/kdbus",             "kdbusfs",    NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
-          NULL,       MNT_IN_CONTAINER },
+          is_kdbus_wanted,       MNT_IN_CONTAINER },
 };
 
 /* These are API file systems that might be mounted by other software,