golang: Fix for out-of-tree builds

RWMJ:

This is half of a downstream Debian patch to fix out-of-tree builds
for golang.

(cherry picked from commit a60212ee99de88591d060a95b30aa0e0cece5832)
fuse: Skip test-fuse-umount-race.sh if backing file does not exist.

(cherry picked from commit f32aef2971497872c179cb16dd1a1d922c46587e)
fuse: Make all the skip messages consistent in this test.

(cherry picked from commit 1fbf0a88f6c4e5648af8ec64e3933683078f4a94)
launch: libvirt: Add -device sga (sgabios).

This feature was added to libvirt in 2011-07-08 so we can assume it
exists.

Thanks: Jiri Jaburek
(cherry picked from commit bed592498d791c5ce6ad722f41dcbfbe243b0a7a)
ruby: add :nodoc: comment for internal methods

This way they are ignored by rdoc.

(cherry picked from commit 917ca11a76863075b4fcb13fe0eec0c2a6a08892)
appliance: Increase udev timeout to 6000s (RHBZ#1096579).

If the image is located on NFS, and the NFS mount is performing a
large copy, then all other NFS operations stop.  This delay can be
large enough that we hit the current 10 minute timeout in udev.

Increasing this to 100 minutes is reported to cure the problem (in
reality we want udev to wait indefinitely).

(cherry picked from commit ef49b297cc56668da01efa637fb80007a76d23dd)
appliance: Update packagelist for Mageia (RHBZ#1102448).

(cherry picked from commit 00d94d95c805ee027a9ef9e67f3979f1faada4a7)
generator: fix daemon functions with optional params but no mandatory params

The
  struct guestfs_$function_args args;
declaration was not emitted in that case, leading to build failure.

(cherry picked from commit 4d8ecb0d30b8e0c49ddb750b5102a2cb67fdd2b5)
appliance: remove extra comma in Mageia's list

Followup of commit 00d94d95c805ee027a9ef9e67f3979f1faada4a7.

Thanks Thierry Vignaud for the notice.

(cherry picked from commit 6577f34a687f339304f20ac703a2e468865a4297)
builder: handle duplicated images (RHBZ#1092753).

Filter the available images, removing the versions with an older
revisions, and duplicates.

(cherry picked from commit b28ef8791a21751b1def9f84108fec14ea73ffa9)
daemon: print parameters for vgchange in error messages

(cherry picked from commit 45db96b00dde2eb9429efbdc2f57bb1bbafafc03)
daemon: grub: show grub-install's output on error if verbose

(cherry picked from commit 844066597dc9ed92c0685c136f613c06276c6132)
appliance: init: properly set PS1 and TERM for virt-rescue (RHBZ#812970).

Setting environment variables such as PS1 for bash before starting it
might not be effective when the startup scripts provided by the
distribution unconditionally change it.
Hence, set PS1 and TERM in a ~/.bashrc, which will be source'd last and
thus be able to set them the way we want.

(cherry picked from commit e6a858907fd7851148440dcfc7cbabc5cee75a71)
launch: libvirt: Only use serial BIOS (sgabios) on x86.

This device is not present at least on ARM.  Unfortunately libvirt
doesn't give us any way to query when the device is present.

This fixes commit bed592498d791c5ce6ad722f41dcbfbe243b0a7a.

(cherry picked from commit 7faa602e8f86702418e11572603badbfbb14f6b7)
builder: Update rhel.sh script for RHEL 7 GA.

Set the rootfs for RHEL 7.x to xfs.  (/boot is ext4)

Remove old RHEL 7 beta & rc releases.

(cherry picked from commit 24800d2e96b668252e30977f3af81aa3b2195eef)
builder: Further updates to RHEL 7 GA script.

The location of the trees have moved ... again.

(cherry picked from commit 99472ab2e925a43e9ba51e62ee66145e92209b8f)
builder: virt-install now seems to require '--serial pty' option.

(cherry picked from commit 73ebaa30668ce7d9e3e413c3abf67a74829dfe5d)
builder: virt-install now requires '--serial pty' parameter.

This updates commit 73ebaa30668ce7d9e3e413c3abf67a74829dfe5d.

(cherry picked from commit d4d6540b24ac82fd7344db10e96270cc0a28aa68)
builder: Fedora: Enable Xen driver support.

See:
https://www.redhat.com/archives/libguestfs/2014-June/thread.html#00045

Notes:

(1) Edit dracut configuration to make sure the change is permanent, in
case kickstart, virt-builder or something else installs a kernel or
runs dracut.

(2) We need to run dracut on the just-installed kernel, not on the
running kernel.  The snippet to do this was copied from the Fedora
cloud kickstart.

Thanks: Olaf Hering, George Dunlap, Dario Faggioli.
(cherry picked from commit 0fa52e4e45d80874bc5ea5f112f74be1d3f3472f)
builder: Update Fedora 20 image, with Xen drivers.

This commit also removes the disk image signature.  These have not
been needed since virt-builder 1.24.1.  No one should be running that
version of virt-builder since there are newer 1.24 branch versions.

(cherry picked from commit 58ea77e79becc14e5ddacc0f37f41fac3a3f14e3)