Add metadata_url and imagefile_url.

web interface.

Most of this commit is about making it easier to create the
descriptors (of any kind) The newimageid_ez page now takes an optional
node_id on which to base the new descriptor; most of the fields are
initialized.

You can also provide optional imageid and osinfo arguments, which
allows for slightly less info to be initialized.

Then on the ShowNode page, the link to create an image will take you
to the snapshot image page if the user has write access to the image,
otherwise to the newimageid_iz page to create and snapshot a new
image descriptor.

Add metadata_url and imagefile_url support in image creation
and lookup.

Add metadata_utl and imagefile_url to the images table; this is to be
used with image export/import.

operating on shared lans.

container.

* Change reboot_prepare to take a -noreboot argument since in general
  we want to control the reboot externally. Just want to run prepare. 

* New openvz variant of create-image that installed on openvz hosts,
  which is called from the server side to reboot/prepare the contaner,
  take the snapshot using tar/imagezip/frisupload, and then restart
  the container.

So what if your testbed has a control network but no experimental
network? In the past you were SOL, but with this commit you can now
create links and lans on the control network that look just like
an experimental network link/lan.

To make this work, ptopgen sports a new option (-C) that will put the
control network links and wires and switches into the ptop file.

libvtop generally operates as normal, but need to arrange for the
physical ports to be put into dual tag/trunk mode, where the native
vlan is the Control network. This is done with by setting attributes
on the lan table entry that indicate dual and what to use for the
native vlan. snmpit looks for these attributes.

There are a couple of places that use the stack name (Control or
Experiment) to determine if a vlan is control or experimental. This is
not longer truu, and so need to use an attribute in the lan table
entry. 

The last bit of the puzzle is that snmpit has to be careful when
disabling trunking on these ports. When this happens, all vlans are
cleard from the ports (by the device layer), including the Control
network itself, which would make the node unreachable. I had to add
some special cases to watch for that, and return the ports to the
control network.

To turn this on, create a ControlNetVlans and enable it. The mapper
looks for this and passes the -C argument to ptopgen.

Nothing special in the NS file, except you have to turn on vlan
encapsulation; tb-set-vlan-emulation vlan

No delay nodes, but linkdelays work okay. Works for openvz containers
as well.

with snmpit -A before booting nodes.

def_parentosid, since that is how ptopgen operates.

span experiments.

libraries (snmpit_test subdir). I suppose we should really commit
to the new test version of snmpit.

While I was in there fixing the bug, I added a "do nothing" option (-n)
and made using rsync checksumming optional (-c).

Every once in a while, I change the version of FreeBSD running on a delay
node (with os_load) and it would blow up because the command line to boot
the delay kernel with would be wrong.

Note that this is not a general fix for default command lines, it is limited
to delay node kernels.

Now let's not worry about who put it there; the important part is that
it is fixed.
(cherry picked from commit 0c9cb66d262568f076a0ec1806e5edc56c6e38a5)

This allows you to pipe into imagezip ala:
     tar cf - dir-o-stuff | imagezip -f - dir-o-stuff.ndz
But of course this only works with "raw" or "regular file" inputs where we
are not seeking around looking for metadata with which to do intelligent
compression.

(cherry picked from commit 030f0a93e4449d4006682fb84777e505e366b7ef)

And a couple of error-printf bugfixes
(cherry picked from commit e31153aee1c7da2bb92d8528f951b34b952d0eda)

Fix up to run sysprep automatically.  Also clear away unattend.xml files to
get rid of potentially sensitive information (e.g. license keys).