Update `check_dpkg` function.

[ieure]

While running build_kernel.sh, I got this message:

Debian/Ubuntu/Mint: missing dependencies, please install:
-----------------------------
sudo apt-get update
sudo apt-get install libncurses5-dev:amd64
-----------------------------
* Failed dependency check

Even though the package it’s complaining about is installed. The command used to determine if a package is installed is:

LC_ALL=C dpkg --list | awk '{print $2}' | grep libncurses

When this is run, it outputs:

libncurses5:amd64
libncurses5-dev:a
libncursesw5:amd6

This is because dpkg truncates the package name to show columnar information.

Instead of using this rather roundabout method, use dpkg-query instead.

[RobertCNelson]

Thanks! merged.