Anaconda 42.26

• Add systemd override to make /usr RW in Dracut (mkolman)
• Update the boot options passed to initrd for dns confgiuration (rvykydal)
• Fix calls to IsConnecting() (champetier.etienne)
• Revert "dracut: Remove 'linear' from modules to load" (vtrefny)
• Revert "Remove 'linear' from list of expected MD RAID levels" (vtrefny)
• security: add a development note for certificates import in initramfs
  (rvykydal)
• security: do not issue warning on existing certificate file during dump
  (rvykydal)