HPCC-2345 Debug fails to build package

The - separator is not allowed in rpms.

Using an underscore SEEMS to work in both Ubuntu and Centos, but without
having tested ever distro version, perhaps no separator at all is safer.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #4549 from richardkchapman/debug-rpms

HPCC-2345 Debug fails to build package

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>