daemon: Check return value of end_stringsbuf.

Found by Coverity.
p2v: Success message should have info logo, not error logo.
p2v: Ensure the current version of virt-p2v is always displayed.

This will help with debugging customer problems.
p2v: Temporarily remove Configure Network button.

We will ship 1.28 without the capability of configuring the network
(ie. DHCP will always be used).
p2v: Remove p2v-iso directory.

As part of reworking the scripts that are used to build the P2V ISO,
first remove the separate p2v-iso directory.  Similar scripts and
documentation will be introduced back into the p2v/ directory in
following commits.
p2v: Add scripts to make disk or kickstart-based P2V ISO.

Two scripts are added, replacing the make targets from the
previous commit:

virt-p2v-make-disk: Builds a virt-p2v disk or USB key using
virt-builder.

virt-p2v-make-kickstart: Builds a kickstart file (only) which can be
fed to livecd-creator or similar tools on Red Hat-derived distros.

Kickstart generation is slightly different: Instead of requiring the
downstream 'libguestfs-pvhelper' package, the kickstart now embeds the
virt-p2v binary(!) making it self-contained and downstream packaging
simpler.

In addition there are documentation changes.
Version 1.27.39.
RHEL 7: Emphasize libguestfs-winsupport package (RHBZ#627468).

This RHEL-only patch changes the error messages when the
inspection code cannot find an operating system inside the guest
image.  For a Windows guest this may happen because the user has not
installed the separate 'libguestfs-winsupport' package.  Therefore we
emphasize that the user may need to install this package.

Notes:

(1) In RHEL there are two pieces of inspection code, the old Perl code
(deprecated upstream) and the new C core inspection API.  Therefore
this patch has to touch two places with essentially the same change.

(2) This patch doesn't try to be clever and detect if it was a Windows
guest.  This should reduce the chance of failure.

Output from (Perl) virt-inspector now looks like this:

 $ virt-inspector disk.img
 No operating system could be detected inside this disk image.

 This may be because the file is not a disk image, or is not a virtual machine
 image, or because the OS type is not understood by virt-inspector.

 If you feel this is an error, please file a bug report including as much
 information about the disk image as possible.

 RHEL notice
 -------------
 libguestfs will return this error for Microsoft Windows guests if the
 separate 'libguestfs-winsupport' package is not installed. If the
 guest is running Microsoft Windows, please try again after installing
 'libguestfs-winsupport'.

Output from guestfish (ie. C core inspection API) now looks like this:

 $ guestfish -i disk.img
 guestfish: no operating system was found on this disk

 RHEL notice
 -------------
 libguestfs will return this error for Microsoft Windows guests if the
 separate 'libguestfs-winsupport' package is not installed. If the
 guest is running Microsoft Windows, please try again after installing
 'libguestfs-winsupport'.
RHEL 7: Remove libguestfs live (RHBZ#798980).

This isn't supported in RHEL 7.
RHEL 7: Remove 9p APIs from RHEL (RHBZ#921710).
RHEL 7: Disable unsupported remote drive protocols (RHBZ#962113).

This disables support for unsupported remote drive protocols:

 * ftp
 * ftps
 * http
 * https
 * tftp
 * gluster
 * iscsi
 * rbd
 * sheepdog
 * ssh

Note 'nbd' is not disabled, and of course 'file' works.

We hope to gradually add some of these back over the lifetime of RHEL 7.