build-unit-test-docker: chown: be more specific

The chown step has shown to take a significant amount of time compared
to other parts of the CI docker image build. Be a bit more granular with
it as the only real need was to ensure other repos could install
generated files under /usr/local/share/

Tested:
- Verified that I could run the script using different user id's
  on the same system against repos that install into /usr/local/share.

Change-Id: I61e43241604f48d66c4e8ab20cabea91eb064bbe
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
1 file changed