make prep-dom0 fails when invoked directly

[emkll]

This error does not occur when running the targets are run during a make all run, only when invoked directly through the prep-dom0 Makefile target.

Steps to reproduce:

1. checkout latest master
2. make prep-dom0
3. observe error:

Deploying Salt config...
local:
    ----------
    sd-workstation.top:
        ----------
        status:
            unchanged
sudo qubesctl top.enable sd-vm-updates
[ERROR   ] An un-handled exception was caught by salt's global exception handler:
SaltRenderError: Could not find relpath for sd-vm-updates.top
Traceback (most recent call last):
  File "/bin/qubesctl", line 98, in <module>
    salt_call()
  File "/usr/lib/python2.7/site-packages/salt/scripts.py", line 391, in salt_call
    client.run()
  File "/usr/lib/python2.7/site-packages/salt/cli/call.py", line 58, in run
    caller.run()
  File "/usr/lib/python2.7/site-packages/salt/cli/caller.py", line 134, in run
    ret = self.call()
  File "/usr/lib/python2.7/site-packages/salt/cli/caller.py", line 204, in call
    ret['return'] = func(*args, **kwargs)
  File "/var/cache/salt/minion/extmods/modules/topd.py", line 74, in enable
    return TopUtils(__opts__, **kwargs).enable(paths, saltenv)
  File "/var/cache/salt/minion/extmods/utils/toputils.py", line 600, in enable
    toppaths, unseen = self.prepare_paths(paths)
  File "/var/cache/salt/minion/extmods/utils/toputils.py", line 453, in prepare_paths
    toppath = self.toppath(path)
  File "/var/cache/salt/minion/extmods/utils/toputils.py", line 332, in toppath
    saltenv = saltenv or self.saltenv(path, saltenv)
  File "/var/cache/salt/minion/extmods/utils/pathutils.py", line 128, in saltenv
    relpath = self.relpath(path)
  File "/var/cache/salt/minion/extmods/utils/pathutils.py", line 486, in relpath
    return self.path(path, saltenv)
  File "/var/cache/salt/minion/extmods/utils/toputils.py", line 269, in path
    return super(TopUtils, self).path(path, saltenv, path_type=path_type)
  File "/var/cache/salt/minion/extmods/utils/pathutils.py", line 445, in path
    raise SaltRenderError('Could not find relpath for {0}'.format(path))
SaltRenderError: Could not find relpath for sd-vm-updates.top
Traceback (most recent call last):
  File "/bin/qubesctl", line 98, in <module>
    salt_call()
  File "/usr/lib/python2.7/site-packages/salt/scripts.py", line 391, in salt_call
    client.run()
  File "/usr/lib/python2.7/site-packages/salt/cli/call.py", line 58, in run
    caller.run()
  File "/usr/lib/python2.7/site-packages/salt/cli/caller.py", line 134, in run
    ret = self.call()
  File "/usr/lib/python2.7/site-packages/salt/cli/caller.py", line 204, in call
    ret['return'] = func(*args, **kwargs)
  File "/var/cache/salt/minion/extmods/modules/topd.py", line 74, in enable
    return TopUtils(__opts__, **kwargs).enable(paths, saltenv)
  File "/var/cache/salt/minion/extmods/utils/toputils.py", line 600, in enable
    toppaths, unseen = self.prepare_paths(paths)
  File "/var/cache/salt/minion/extmods/utils/toputils.py", line 453, in prepare_paths
    toppath = self.toppath(path)
  File "/var/cache/salt/minion/extmods/utils/toputils.py", line 332, in toppath
    saltenv = saltenv or self.saltenv(path, saltenv)
  File "/var/cache/salt/minion/extmods/utils/pathutils.py", line 128, in saltenv
    relpath = self.relpath(path)
  File "/var/cache/salt/minion/extmods/utils/pathutils.py", line 486, in relpath
    return self.path(path, saltenv)
  File "/var/cache/salt/minion/extmods/utils/toputils.py", line 269, in path
    return super(TopUtils, self).path(path, saltenv, path_type=path_type)
  File "/var/cache/salt/minion/extmods/utils/pathutils.py", line 445, in path
    raise SaltRenderError('Could not find relpath for {0}'.format(path))
salt.exceptions.SaltRenderError: Could not find relpath for sd-vm-updates.top
DOM0 configuration failed, not continuing
Makefile:126: recipe for target 'prep-dom0' failed
make: *** [prep-dom0] Error 1