Update variables.sh: Add ALLSKY_EXIT_STOP

When the service should be stopped but there's no error.

Author: EricClaeys

variables.sh

@@ -297,6 +297,7 @@ if [[ -z "${ALLSKY_VARIABLE_SET}" || ${1} == "--force" ]]; then
 	# Anything at or above EXIT_ERROR_STOP is unrecoverable and the service must be stopped
 	ALLSKY_EXIT_ERROR_STOP=100		# unrecoverable error - need user action so stop service
 	ALLSKY_EXIT_NO_CAMERA=101		# cannot find camera
+	ALLSKY_EXIT_STOP=102			# Stop, but no error
 
 	# Name of the Pi's OS in lowercase.
 	ALLSKY_PI_OS="$( grep VERSION_CODENAME /etc/os-release )"