vm: return full copy of the conf data on status()

It is unsafe for status() to return a shallow copy
of the Vm.conf data.

Many modules (e.g. copy, json) of the python standard
libary make use of the iteritems() method when dealing
with dicts, so they can explode while iterating on
data being mutated by the creation thread.

This can be triggered just if someone (Engine) queries for
Vm status while the creation thread is running, like

Traceback (most recent call last):
   File "/usr/lib/python2.6/site-packages/yajsonrpc/__init__.py", line 242, in sendReply
     encodedObjects.append(response.encode())
   File "/usr/lib/python2.6/site-packages/yajsonrpc/__init__.py", line 140, in encode
     return json.dumps(res, 'utf-8')
   File "/usr/lib64/python2.6/json/__init__.py", line 237, in dumps
     **kw).encode(obj)
   File "/usr/lib64/python2.6/json/encoder.py", line 367, in encode
     chunks = list(self.iterencode(o))
   File "/usr/lib64/python2.6/json/encoder.py", line 309, in _iterencode
     for chunk in self._iterencode_dict(o, markers):
   File "/usr/lib64/python2.6/json/encoder.py", line 275, in _iterencode_dict
     for chunk in self._iterencode(value, markers):
[...]
RuntimeError: dictionary changed size during iteration

This patch makes it always return a full copy.

Change-Id: I604f8534c9380d289633df4a8151699ab0d97e34
Bug-Url: https://bugzilla.redhat.com/1148583
Signed-off-by: Francesco Romani <fromani@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/34147
Reviewed-by: Nir Soffer <nsoffer@redhat.com>
Reviewed-by: Michal Skrivanek <michal.skrivanek@redhat.com>
Reviewed-by: Martin Polednik <mpolednik@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>