use PLEX_MEDIA_SERVER_INFO_DEVICE=docker to identify to pms using a docker image, fix quotes on variable, shellcheck

Author: sparklyballs

Dockerfile

@@ -1,14 +1,14 @@
 FROM lsiobase/xenial
 MAINTAINER Stian Larsen, sparklyballs
 
-# package version
-ENV PLEX_INSTALL="https://plex.tv/downloads/latest/1?channel=8&build=linux-ubuntu-x86_64&distro=ubuntu"
 
 # global environment settings
 ENV DEBIAN_FRONTEND="noninteractive" \
 PLEX_DOWNLOAD="https://downloads.plex.tv/plex-media-server" \
+PLEX_INSTALL="https://plex.tv/downloads/latest/1?channel=8&build=linux-ubuntu-x86_64&distro=ubuntu" \
 PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR="/config/Library/Application Support" \
 PLEX_MEDIA_SERVER_HOME="/usr/lib/plexmediaserver" \
+PLEX_MEDIA_SERVER_INFO_DEVICE=docker \
 PLEX_MEDIA_SERVER_MAX_PLUGIN_PROCS="6"
 
 # install packages

root/etc/cont-init.d/40-chown-files

@@ -4,7 +4,7 @@
 if [ ! -d "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}" ]; then
 	mkdir -p "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}"
 	chown abc:abc "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}"
-elif [ ! "$(stat -c %u ${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR})" = "$PUID" ]; then
+elif [ ! "$(stat -c %u "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}")" = "$PUID" ]; then
 	echo "Change in ownership detected, please be patient while we chown existing files"
 	echo "This could take some time"
 	chown abc:abc -R \