host provided XDG_DATA_DIRS not handled correctly

[ttimasdf]

distrobox/distrobox-enter

Lines 357 to 367 in cdaa860

	# Ensure the standard FHS program paths are in XDG_DATA_DIRS environment
	standard_paths="/usr/local/share /usr/share"
	container_paths="${XDG_DATA_DIRS:=}"
	# add to the XDG_DATA_DIRS only after the host's paths, and only if not already present.
	for standard_path in ${standard_paths}; do
	if [ -n "${container_paths##*:"${standard_path}"*}" ]; then
	container_paths="${container_paths}:${standard_path}"
	fi
	done
	result_command="${result_command}
	--env \"XDG_DATA_DIRS=${container_paths}\""

When launching distrobox-enter with empty XDG_DATA_DIRS, standard paths are not added to environment variable.

++ standard_paths='/usr/local/share /usr/share'
++ container_paths=
++ for standard_path in '${standard_paths}'
++ '[' -n '' ']'
++ for standard_path in '${standard_paths}'
++ '[' -n '' ']'
++ result_command='docker exec
# skipped lines..
		--env "PATH=/usr/local/sbin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
		--env "XDG_DATA_DIRS="'
++ set +x

This happens when launching integrated VSCode app from GNOME 2 menu launcher.

environment: bash 4.2 on CentOS 7

sh-4.2$ sh --version
GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)