Please backport (or let it in via rebase) the following commit to RHEL 
7.7.  This makes debugging more pleasant (don't understimate how
important this is for those who look at giant QEMU command-lines without
any line breaks, all the time).  And, as DanPB noted on IRC, we'll now
be able to read the QEMU command-line when people copy / paste it in
bugs, without making our eyes bleed.

    commit 07c9d6601d0b440acd13794b258bdcb570ae93f4
    Author: Daniel P. Berrangé <berrange>
    Date:   Fri Dec 14 12:07:08 2018 +0000

        qemu: use line breaks in command line args written to log
    
        The QEMU command line arguments are very long and currently all written
        on a single line to /var/log/libvirt/qemu/$GUEST.log. This introduces
        logic to add line breaks after every env variable and "-" optional
        argument, and every positional argument. This will create a clearer log
        file, which will in turn present better in bug reports when people cut +
        paste from the log into a bug comment.
    
        An example log file entry now looks like this:
    
          2018-12-14 12:57:03.677+0000: starting up libvirt version: 5.0.0, qemu version: 3.0.0qemu-3.0.0-1.fc29, kernel: 4.19.5-300.fc29.x86_64, hostname: localhost.localdomain
          LC_ALL=C \
          PATH=/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin \
          HOME=/home/berrange \
          USER=berrange \
          LOGNAME=berrange \
          QEMU_AUDIO_DRV=none \
          /usr/bin/qemu-system-ppc64 \
          -name guest=guest,debug-threads=on \
          -S \
          -object secret,id=masterKey0,format=raw,file=/home/berrange/.config/libvirt/qemu/lib/domain-33-guest/master-key.aes \
          -machine pseries-2.10,accel=tcg,usb=off,dump-guest-core=off \
          -m 1024 \
          -realtime mlock=off \
          -smp 1,sockets=1,cores=1,threads=1 \
          -uuid c8a74977-ab18-41d0-ae3b-4041c7fffbcd \
          -display none \
          -no-user-config \
          -nodefaults \
          -chardev socket,id=charmonitor,fd=23,server,nowait \
          -mon chardev=charmonitor,id=monitor,mode=control \
          -rtc base=utc \
          -no-shutdown \
          -boot strict=on \
          -device qemu-xhci,id=usb,bus=pci.0,addr=0x1 \
          -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x2 \
          -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \
          -msg timestamp=on
          2018-12-14 12:57:03.730+0000: shutting down, reason=failed

        Signed-off-by: Daniel P. Berrangé <berrange>