Fix deb build error "cfg_in_dir_path not defined"

19:28:24 Traceback (most recent call last):
19:28:24 File "/w/workspace/packaging-build-deb-carbon/packaging/packages/build.py", line 133, in <module>
19:28:24 deb_lib.build_deb(build)
19:28:24 File "/w/workspace/packaging-build-deb-carbon/packaging/packages/deb/lib.py", line 66, in build_deb
19:28:24 shutil.copy(unitfile_path, cfg_in_dir_path)
19:28:24 NameError: global name 'cfg_in_dir_path' is not defined
19:28:24 Build step 'Execute shell' marked build as failure
19:28:24 $ ssh-agent -k

Showing in all recent deb build jobs.