Once it's plugged in, the <listen> element will be an optional
replacement for the "listen" attribute that graphics elements already
have. If the <listen> element is type='address', it will have an
attribute called 'address' which will contain an IP address or dns
name that the guest's display server should listen on. If, however,
type='network', the <listen> element should have an attribute called
'network' that will be set to the name of a network configuration to
get the IP address from.

* docs/schemas/domain.rng: updated to allow the <listen> element

* docs/formatdomain.html.in: document the <listen> element and its
  attributes.

* src/conf/domain_conf.[hc]:

  1) The domain parser, formatter, and data structure are modified to
     support 0 or more <listen> subelements to each <graphics>
     element. The old style "legacy" listen attribute is also still
     accepted, and will be stored internally just as if it were a
     separate <listen> element. On output (i.e. format), the address
     attribute of the first <listen> element of type 'address' will be
     duplicated in the legacy "listen" attribute of the <graphic>
     element.

  2) The "listenAddr" attribute has been removed from the unions in
     virDomainGRaphicsDef for graphics types vnc, rdp, and spice.
     This attribute is now in the <listen> subelement (aka
     virDomainGraphicsListenDef)

  3) Helper functions were written to provide simple access
     (both Get and Set) to the listen elements and their attributes.

* src/libvirt_private.syms: export the listen helper functions

* src/qemu/qemu_command.c, src/qemu/qemu_hotplug.c,
  src/qemu/qemu_migration.c, src/vbox/vbox_tmpl.c,
  src/vmx/vmx.c, src/xenxs/xen_sxpr.c, src/xenxs/xen_xm.c

  Modify all these files to use the listen helper functions rather
  than directly referencing the (now missing) listenAddr
  attribute. There can be multiple <listen> elements to a single
  <graphics>, but the drivers all currently only support one, so all
  replacements of direct access with a helper function indicate index
  "0".

* tests/* - only 3 of these are new files added explicitly to test the
  new <listen> element. All the others have been modified to reflect
  the fact that any legacy "listen" attributes passed in to the domain
  parse will be saved in a <listen> element (i.e. one of the
  virDomainGraphicsListenDefs), and during the domain format function,
  both the <listen> element as well as the legacy attributes will be
  output.

The most common cause of errors with rhel5-api turn on was missing
"(type ioemu)" in sexpr or its equivalent in XM configuration file. This
happens because the presence of that part in sexpr (or cfg) depends on
xen version the host is running. Let's avoid it by explicitly specifying
interface model which ensures "type ioemu" will always be emitted.

This patch adds

    <model type='e1000'/>

withing the interface element in all affected xml files. And

    (model 'e1000')

to all corresponding sexpr files with similar fix to cfg files. Such
configuration works regardless on Xen version.

* tests/qemuxml2argvdata/qemuxml2argv-sound.args
  tests/qemuxml2argvdata/qemuxml2argv-sound.xml
  tests/sexpr2xmldata/sexpr2xml-fv-sound-all.sexpr
  tests/sexpr2xmldata/sexpr2xml-fv-sound-all.xml
  tests/sexpr2xmldata/sexpr2xml-fv-sound.sexpr
  tests/sexpr2xmldata/sexpr2xml-fv-sound.xml
  tests/xmconfigdata/test-fullvirt-sound.cfg
  tests/xmconfigdata/test-fullvirt-sound.xml
  tests/xml2sexprdata/xml2sexpr-fv-sound.sexpr
  tests/xml2sexprdata/xml2sexpr-fv-sound.xml: other regression
  tests from previous commit
Daniel