Why does the Leapp upgrade fails with error "IOError Errno 30 Read-only file system /boot/vmlinuz-upgrade.x86_64" ?

Issue

• The Leapp upgrade fails producing the below trace back.

Traceback (most recent call last):
  File "/usr/lib64/python2.7/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/usr/lib64/python2.7/multiprocessing/process.py", line 114, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/lib/python2.7/site-packages/leapp/repository/actor_definition.py", line 72, in _do_run
    actor_instance.run(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/leapp/actors/__init__.py", line 290, in run
    self.process(*args)
  File "/usr/share/leapp-repository/repositories/system_upgrade/common/actors/initramfs/upgradeinitramfsgenerator/actor.py", line 40, in process
    upgradeinitramfsgenerator.process()
  File "/usr/share/leapp-repository/repositories/system_upgrade/common/actors/initramfs/upgradeinitramfsgenerator/libraries/upgradeinitramfsgenerator.py", line 206, in process
    generate_initram_disk(context)
  File "/usr/share/leapp-repository/repositories/system_upgrade/common/actors/initramfs/upgradeinitramfsgenerator/libraries/upgradeinitramfsgenerator.py", line 179, in generate_initram_disk
    copy_boot_files(context)
  File "/usr/share/leapp-repository/repositories/system_upgrade/common/actors/initramfs/upgradeinitramfsgenerator/libraries/upgradeinitramfsgenerator.py", line 195, in copy_boot_files
    context.copy_from(os.path.join('/artifacts', kernel), content.kernel_path)
  File "/usr/share/leapp-repository/repositories/system_upgrade/common/libraries/mounting.py", line 245, in copy_from
    shutil.copy2(self.full_path(src), dst)
  File "/usr/lib64/python2.7/shutil.py", line 130, in copy2
    copyfile(src, dst)
  File "/usr/lib64/python2.7/shutil.py", line 83, in copyfile
    with open(dst, 'wb') as fdst:
IOError: [Errno 30] Read-only file system: '/boot/vmlinuz-upgrade.x86_64'