V2: Use virAsprintf instead of snprintf/strdup

The xend driver will generate a virDomainNetDef ifname if one is not
specified in xend sexpr, even if domain is inactive.  The result is
network interface XML containing 'vif-1.Y' on dev attribute of target
element, e.g.

  <interface type='bridge'>
    <target dev='vif-1.0'/>
    ...

This patch changes the behavior to only generate the ifname if not
specified in xend sexpr *and* domain is not inactive (id != -1).

It costs quite a few processor cycles to go through printf parsing
just to determine that we only meant to append.

* src/xen/xend_internal.c (xend_op_ext): Consolidate multiple
printfs into one.
* src/qemu/qemu_command.c (qemuBuildWatchdogDevStr)
(qemuBuildUSBInputDevStr, qemuBuildSoundDevStr)
(qemuBuildSoundCodecStr, qemuBuildVideoDevStr): Likewise.
(qemuBuildCpuArgStr, qemuBuildCommandLine): Prefer virBufferAdd
over virBufferVsprintf for trivial appends.
* src/phyp/phyp_driver.c (phypExec, phypUUIDTable_Push)
(phypUUIDTable_Pull): Likewise.
* src/conf/nwfilter_conf.c (macProtocolIDFormatter)
(arpOpcodeFormatter, formatIPProtocolID, printStringItems)
(virNWFilterPrintStateMatchFlags, virNWIPAddressFormat)
(virNWFilterDefFormat): Likewise.
* src/security/virt-aa-helper.c (main): Likewise.
* src/util/sexpr.c (sexpr2string): Likewise.
* src/xenxs/xen_sxpr.c (xenFormatSxprChr): Likewise.
* src/xenxs/xen_xm.c (xenFormatXMDisk): Likewise.

Make: passed
Make check: passed
Make syntax-check: passed

this is the commit to introduce the function to create new character
device definition for the domain as advised by Cole Robinson
<crobinso@redhat.com>.

The function is used on the relevant places and also new tests has
been added.
Signed-off-by: NMichal Novotny <minovotn@redhat.com>

this is the patch to add support for multiple serial ports to the
libvirt Xen driver. It support both old style (serial = "pty") and
new style (serial = [ "/dev/ttyS0", "/dev/ttyS1" ]) definition and
tests for xml2sexpr, sexpr2xml and xmconfig have been added as well.

Written and tested on RHEL-5 Xen dom0 and working as designed but
the Xen version have to have patch for RHBZ #614004 but this patch
is for upstream version of libvirt.

Also, this patch is addressing issue described in RHBZ #670789.
Signed-off-by: NMichal Novotny <minovotn@redhat.com>