scripts/installer.sh fix APT_SYSTEMCTL_START error

fix error: 'sh: 411: APT_SYSTEMCTL_START: parameter not set' on certain debian distributions

Signed-off-by: Jay Stapleton <jay@tailscale.com>

scripts/installer.sh

@@ -24,6 +24,7 @@ main() {
 	VERSION=""
 	PACKAGETYPE=""
 	APT_KEY_TYPE="" # Only for apt-based distros
+	APT_SYSTEMCTL_START=false # Only needs to be true for Kali
 
 	if [ -f /etc/os-release ]; then
 		# /etc/os-release populates a number of shell variables. We care about the following: