This patch preserves backward compatibility of
deb package names with previous CMake versions
but similarly to CPack/RPM allows to change
package name format and supports DEB-DEFAULT
setting that produces proper Debian package names.
The changes in commit 47b060ae (CPackDeb: allow empty directories in
component packages, 2015-09-21), commit b58de9fe (CPack: allow packaging
of empty directories, 2015-09-21), and commit b761e90d (CPack: remove
accidental changes, 2015-09-22) regressed packaging of CMake itself.
Revert the changes until they can be revised and rebased on other
changes that make additional fixes.