smf_method(5): fix description of security_flags

@@ -313,13 +313,14 @@
            security-flags(5).
 
 
            The "default" keyword specifies those flags specified in
            svc:/system/process-security.  The "all" keyword enables all flags,
-           the "none" keyword enables no flags.  Further flags may be added by
-           specifying their name, or removed by specifying their name prefixed
-           by '-' or '!'.
+           the "none" keyword enables no flags.  The "current" keyword
+           specifies the current flags.  Flags may be added by specifying
+           their name (optionally preceded by '+'), and removed by preceding
+           their name with '-').
 
 
            Use of "all" has associated risks, as future versions of the system
            may include further flags which may harm poorly implemented
            software.