sysutils/nut*: Remove bash_completion dependency

Even though bash completion scripts are installed, bash_completion
need not be installed, reducing the port and package footprint.
Should a person actually need bash_completion, it can be installed
separately by the user.

PR: 267214
Reported by: Mel Pilgrim <ports.maintainer@evilphi.com>
MFH: 2022Q4

(cherry picked from commit 6d2af9e3f07a2473b50b02388a58708ad5015cf5)