Fix parse_protobuf
Fix parse_protobuf

SRCDIR was removed some time ago, use lookup_file_path() instead to
locate aqd.conf.defaults.

Change-Id: Ie9446fb151df85c365dbb8850eba20d7b112a111
Reviewed-by: Priya Joshi <3c6cfa6f57440adfc837c4ad04483313acbc2582@morganstanley.com>

quattor/aquilon,guillaume-philippon/aquilon,quattor/aquilon,guillaume-philippon/aquilon,quattor/aquilon,guillaume-philippon/aquilon