testing: Install a package via apt-get to get a second SWIMA software event

This installs tmux and its two dependencies libevent-2.0-5 and libutempter0.
For the tnc/tnccs-20-ev-pt-tls test scenario older, apparently replaced
versions of these packages are entered to the collector.db database, so that
dummy SWID tags for these packages can be requested via SWIMA.

testing/scripts/build-baseimage

@@ -16,7 +16,7 @@ INC=automake,autoconf,libtool,bison,flex,gperf,pkg-config,gettext,less,locales
 INC=$INC,build-essential,libgmp-dev,libldap2-dev,libcurl4-openssl-dev,ethtool
 INC=$INC,libxml2-dev,libtspi-dev,libsqlite3-dev,openssh-server,tcpdump,psmisc
 INC=$INC,openssl,vim,sqlite3,conntrack,gdb,cmake,libltdl-dev,liblog4cxx10-dev
-INC=$INC,libboost-thread-dev,libboost-system-dev,git-core,iperf,htop,screen
+INC=$INC,libboost-thread-dev,libboost-system-dev,git-core,iperf,htop
 INC=$INC,gnat,gprbuild,acpid,acpi-support-base,libldns-dev,libunbound-dev
 INC=$INC,dnsutils,libsoup2.4-dev,ca-certificates,unzip,libsystemd-dev
 INC=$INC,python,python-setuptools,python-dev,python-pip,apt-transport-https
@@ -36,6 +36,8 @@ stretch)
 esac
 SERVICES="apache2 dbus isc-dhcp-server slapd bind9 freeradius"
 INC=$INC,${SERVICES// /,}
+# packages to install via APT, for SWIMA tests
+APT="tmux"
 # additional services to disable
 SERVICES="$SERVICES systemd-timesyncd.service"
 
@@ -117,6 +119,8 @@ log_status $?
 
 log_action "Update package sources"
 execute_chroot "apt-get update"
+log_action "Install packages via APT"
+execute_chroot "apt-get -y install $APT"
 log_action "Install packages from custom repo"
 execute_chroot "apt-get -y upgrade"