LU-15758 build: Client module DEB can't be installed on Debian

LU-15758 build: Client module DEB can't be installed on Debian

Building DEB package lustre-client-modules-*.deb depends
since commit 32c4b80192652f55bcef5786e4ec683e85234c04 on
package linux-generic. This package is however available
on Ubuntu distributions, but not e.g. on Debian distribution.
As a consequence the built package lustre-client-modules-*.deb
cannot be installed on Debian due to non-existing package
dependency.

Lustre-change: https://review.whamcloud.com/47087
Lustre-commit: d409f74274754c87cd14a7f0a19f8d46f6496eb1

Test-Parameters: trivial clientdistro=ubuntu2004
Signed-off-by: Thomas Stibor <t.stibor@gsi.de>
Change-Id: Ia541aaede7d779c4dd2f81f896a6be8a797780b3
Reviewed-on: https://review.whamcloud.com/47777
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>