make help message consistant with create_test

scripts/Tools/component_generate_baseline

@@ -36,9 +36,9 @@ OR
                         help="Use custom baseline dir")
 
     parser.add_argument("-o", "--allow-baseline-overwrite", action="store_true",
-                        help="If the generate baseline option is specified with a baseline directory option "
-                        "existing tests in that directory will not be overwritten unless this flag is provided."
-                        "You can use bless-test-results to bless baselines from a recent run.")
+                        help="By default an attempt to overwrite an existing baseline directory "
+                        "will raise an error. Specifying this option allows "
+                        "existing baseline directories to be silently overwritten.")
 
     args = parser.parse_args(args[1:])