Protecting against rm -rf / is now POSIXLY_CORRECT per posix 1003.1

edition 2013. No need anymore to disable the protection if one set
the POXILY_CORRECT environment variable.

Reviewed by:	imp
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D4092

bin/rm/rm.1

@@ -32,7 +32,7 @@
 .\"	@(#)rm.1	8.5 (Berkeley) 12/5/94
 .\" $FreeBSD$
 .\"
-.Dd April 25, 2013
+.Dd November 7, 2015
 .Dt RM 1
 .Os
 .Sh NAME
@@ -234,7 +234,7 @@ not the standard error output.
 The
 .Nm
 command conforms to
-.St -p1003.2 .
+.St -p1003.1-2013 .
 .Pp
 The simplified
 .Nm unlink

bin/rm/rm.c

@@ -155,8 +155,7 @@ main(int argc, char *argv[])
 	}
 
 	checkdot(argv);
-	if (getenv("POSIXLY_CORRECT") == NULL)
-		checkslash(argv);
+	checkslash(argv);
 	uid = geteuid();
 
 	(void)signal(SIGINFO, siginfo);