UBUNTU: [Packaging] dkms-build -- add support for unversioned overrides

UBUNTU: [Packaging] dkms-build -- add support for unversioned overrides

We allow package specific overrides for dkms-build.  However some
packages have versions in their names.  To make these easier to handle
when the version changes add optional unversioned overrides.  Where a
package ends with a -NNN version look for overrides in the full name
and with a (literal) -N suffix.

BugLink: http://bugs.launchpad.net/bugs/1764792
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Andy Whitcroft <andy.whitcroft@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>