login.conf(5): update commented-out standard, too

MAIL now has a mail capability, instead, as of r357560.

usr.bin/login/login.conf

@@ -129,7 +129,8 @@ russian|Russian Users Accounts:\
 #standard:\
 #	:copyright=/etc/COPYRIGHT:\
 #	:welcome=/var/run/motd:\
-#	:setenv=MAIL=/var/mail/$,BLOCKSIZE=K:\
+#	:setenv=BLOCKSIZE=K:\
+#	:mail=/var/mail/$:\
 #	:path=~/bin /bin /usr/bin /usr/local/bin:\
 #	:manpath=/usr/share/man /usr/local/man:\
 #	:nologin=/var/run/nologin:\