And release notes for previous change (MP_STATE_DIRECTORY)

The change has also been updated in
https://www.monitoring-plugins.org/doc/state-retention.html

NEWS

@@ -17,6 +17,8 @@ This file documents the major additions and syntax changes between releases.
 	  but accepted for backward-compatibility
 	check_ide_smart -0/--auto-off, -1/--auto-on and -i/--immediate: options have
 	  been disabled because they were broken
+	State retention: the NAGIOS_PLUGIN_STATE_DIRECTORY environment variable has been
+	  renamed MP_STATE_DIRECTORY. The old variable will continue to work in v1.6.x
 
 1.5 2nd October 2013
 	ENHANCEMENTS

lib/utils_base.c

@@ -420,7 +420,6 @@ char* _np_state_calculate_location_prefix(){
 	/* Do not allow passing MP_STATE_DIRECTORY in setuid plugins
 	 * for security reasons */
 	if (mp_suid() == FALSE) {
-		/* FIXME: Undocumented */
 		env_dir = getenv("MP_STATE_DIRECTORY");
 		if(env_dir && env_dir[0] != '\0')
 			return env_dir;