permissions: docs - updated reference to blocklist

src/modules/permissions/config/register.deny

@@ -21,6 +21,6 @@ ALL : "^sip:.*1\.2\.3\.4$"
 # provide a perfect security, as everybody can register arbitrary
 # domains that point to any IP. To prevent this the usage of hostnames
 # and domains in the Contact header field should be avoided.
-# A better solution to this problem is the usage of the dst_blacklist
+# A better solution to this problem is the usage of the dst_blocklist
 # feature in the openser core. All "critical" IPs should be added to
 # this list.