better test for package installed or not.

root/etc/cont-init.d/50-plex-update

@@ -5,9 +5,10 @@
        	cp /defaults/plexmediaserver /etc/default/plexmediaserver
 
 # test if plex is installed and try re-pulling latest if not
-if dpkg -s plexmediaserver > /dev/null 2>&1 ; then
+if (dpkg --get-selections plexmediaserver | grep -wq "install"); then
 :
-else echo "for some reason plex doesn't appear to be installed, pulling a new copy and exiting out of update script"
+else
+echo "for some reason plex doesn't appear to be installed, pulling a new copy and exiting out of update script"
 curl -o /tmp/plexmediaserver.deb -L \
        	"${PLEX_INSTALL}" && \
 dpkg -i --force-confold /tmp/plexmediaserver.deb