Fix manager bug (can't destroy a session while a thread is using it!)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6698 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/manager.h

@@ -82,6 +82,8 @@ struct mansession {
 	int fd;
 	/*! Whether or not we're busy doing an action */
 	int busy;
+	/*! Whether or not we're "dead" */
+	int dead;
 	/*! Logged in username */
 	char username[80];
 	/*! Authentication challenge */