Update the MySQL voicemail_data contrib script to reflect Asterisk 11 changes

All voicemails now have a 'msg_id' included in their metadata.  The ODBC
message storage backend now requires this column; as such, the MySQL contrib
script that creates the voicemail_data table has been updated with the appropriate
column information.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@370820 65c4cc65-6c06-0410-ace0-fbb531ad65f3

contrib/realtime/mysql/voicemail_data.sql

@@ -23,7 +23,9 @@ CREATE TABLE voicemail_data (
 	-- Value of the channel variable VM_CATEGORY, if set
 	category CHAR(30),
 	-- Length of the message, in seconds
-	duration INT(11)
+	duration INT(11),
+	-- Unique identifier for the message
+	msg_id CHAR(32)
 );