Devserver: make the shadow file easier to use

Using the shadow config that is installed with the devserver is a pain.
Instead, let's always use it from the source dir.

Otherwise in order to propagate shadow config changes you needed to

cros_workon --host start cros-devutils
sudo emerge -1 cros-devutils

Now after this change it always just works after you save the file.

BUG=None
TEST=Ran it and checked shadow_config path.

Change-Id: I1ea9741a4463f1516ad7d3f3f8c82bfd9cbae559
Reviewed-on: https://chromium-review.googlesource.com/67003
Reviewed-by: Chris Sosa <sosa@chromium.org>
Tested-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Chris Sosa <sosa@chromium.org>
2 files changed