Bug found whilst making road

Summary:

Steps to reproduce:

  1. have house
  2. make road after
    develop-2924 (x64)
    …/fixture_fabricator/fixture_fabricator_component.lua:157: attempt to index local ‘bc’ (a nil value)
    stack traceback:
    [C]: ?
    …/fixture_fabricator/fixture_fabricator_component.lua:157: in function ‘_are_dependencies_satisfied’
    …/fixture_fabricator/fixture_fabricator_component.lua:202: in function ‘_start_project’
    …/fixture_fabricator/fixture_fabricator_component.lua:68: in function ‘set_active’
    …ruction_progress/construction_progress_component.lua:73: in function 'set_active’
    stonehearth/services/server/build/build_service.lua:101: in function 'cb’
    stonehearth/services/server/build/build_service.lua:82: in function '_call_all_children’
    stonehearth/services/server/build/build_service.lua:78: in function '_call_all_children’
    stonehearth/services/server/build/build_service.lua:78: in function '_call_all_children’
    stonehearth/services/server/build/build_service.lua:98: in function 'set_active’
    stonehearth/call_handlers/build_call_handler.lua:19: in function <stonehearth/call_handlers/build_call_handler.lua:18>
    develop-2924 (x64)
    c++ exception: lua runtime error
    stack traceback: