This can be useful when user has this UEFI boot order e.g.:

                 Windows | grub | Linux

  And decides to boot into grub/Linux. In case the autorelabel service
  is being run after the boot into grub, then the reboot after the
  autorelabel is done will cause user to boot into Windows again...

  This change should make the behaviour more intuitive for the user.

network-functions uses awk to tranform the mac address to upper case.
Replace awk with tr which is two order of magnitude faster:

    $ time awk '{ print toupper($0) }' </usr/share/dict/words >/dev/null

    real    0m0,227s
    user    0m0,224s
    sys     0m0,004s
    $ time tr '[a-z]' '[A-Z]' </usr/share/dict/words >/dev/null

    real    0m0,005s
    user    0m0,000s
    sys     0m0,005s

Also use here-strings instead of spawning a subshell and a pipe.

Signed-off-by: Matteo Croce <mcroce@redhat.com>

  ... Without appending the 'ro' to mount options of '/' mount point the
  system will be still mounted as read-write, even when READONLY=yes.

  Instead of displaying messages without context, like this:

  ./network-functions: line 571: echo: write error: Invalid argument
  ./network-functions: line 598: echo: write error: Permission denied

  We will now display pretty error messages (via net_log) about what has
  actually failed...

  This has been requested by our customer:
  https://bugzilla.redhat.com/show_bug.cgi?id=1542514

  They have sane default values in kernel for IBM machines as well:
  https://bugzilla.redhat.com/show_bug.cgi?id=1493069

  More info: https://bugzilla.redhat.com/show_bug.cgi?id=1554690

  Resolves: #1553093

  More info: https://bugzilla.redhat.com/show_bug.cgi?id=1518429