By enabling the caller to override the default project file name with
an empty string, we enable the ability to provide project settings
directly in the sonar-properties field. This removes the requirement
for a "sonar-project.properties" file in the repo.
Change-Id: Ia1069417d3bb2a742a68d6113fbd1d8e0374cbdc Signed-off-by: Eric Ball <eball@linuxfoundation.org>