Simplify UPDATING entry.

Thanks to adamw@ for suggesting me this wording.

UPDATING

@@ -9,24 +9,16 @@ you update your ports collection, before attempting any port upgrades.
   AFFECTS: users of net/asterisk13 with PJSIP (default on) and SRTP (default off) options enabled
   AUTHOR: madpilot@FreeBSD.org
 
-  Due to asterisk13 requiring conflicting port options for the net/pjsip
-  dependency when the SRTP option is enabled together with the PJSIP
-  one I have created a new slave port to pjsip to enforce the
-  required option so asterisk can enforce that option with a
-  conditional dependency.
+  This applies ONLY TO USERS COMPILING FROM PORTS:
+  To avoid dependency problems, you must remove the pjsip port
+  before upgrading asterisk13.
 
-  Users building custom packages with poudriere should have no
-  problems, since pkgng is able to handle the change automatically.
+    # pkg delete pjsip
+    # portmaster -a
 
-  For users compiling from ports a simple update of asterisk will
-  keep it working because the already installed pjsip port will
-  satisfy the dependency. They anyway should, when convenient,
-  disinstall the pjsip port(this will also disinstall asterisk13)
-  and rebuild asterisk13 to force it to grab the correct dependency
-  to avoid problems with future updates.
+  These steps are unnecessary for those using binary packages.
 
-  Please check the 20150323 entry in this file which has some
-  background about this problem.
+  Please see the 20150323 entry for background about this problem.
 
 20150501:
   AFFECTS: users of graphics/qgis