simplify supervised vs. standalone mode detection; also fix the docs

releng/README

@@ -229,10 +229,15 @@ When exiting prematurely, make sure to call function cleanup.
 
                Variables, general options, helper functions
 
+The master script run_all_auto sets this variable:
+
+  RELENG_SCRIPT_RUN_BY_RUN_ALL_AUTO
+                    1=supervised, the script is run by run_all_auto script
+                    else=standalone, the script is run in standalone mode 
+
 The code piece inc/releng_getopts.inc should get executed inline at the
-start of a test script.
-It initializes the following variables and sets some of them according
-to the general options of the test suite:
+start of a test script. It initializes the following variables and sets
+some of them according to the general options of the test suite:
 
   SELF              basename $0
 
@@ -250,17 +255,12 @@ to the general options of the test suite:
   SPECIFIC_HELP     0=normal operation, 1=print help text of script and exit 0
                     Default 0. Setable to 1 by option -h.
 
-  RELENG_STANDALONE 0=standalone, 1=supervised by run_all_auto script,
-                    -1=undefined.
-
-  RELENG_PARENT     Name of the parent process. Default: unknown_parent
-
 The code piece inc/releng_getopts.inc defines the following functions
 for use by the single tests:
 
   standalone_or_supervised This is internally called routine to find
                            out the running mode of the scripts - standalone,
-                           supervised by run_all_auto, or unknown.
+                           supervised by run_all_auto.
 			   No need to call it from the scripts themselves.
 
   print_help        Prints the help text for general options.