Clarified the meaning of the callwaiting variable in the zapata.conf file.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@43165 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configs/zapata.conf.sample

@@ -261,7 +261,10 @@ usecallerid=yes
 ;
 hidecallerid=no
 ;
-; Whether or not to enable call waiting on FXO lines
+; Whether or not to enable call waiting on internal extensions
+; With this set to 'yes', busy extensions will hear the call-waiting
+; tone, and can use hook-flash to switch between callers. The Dial()
+; app will not return the "BUSY" result for extensions.
 ;
 callwaiting=yes
 ;