Adds cdr logging of calls resulting in CONGESTION

Applies a patch made a long time ago by alecdavis which adds a CDR feature for logging
calls that failed due to congestion.

(closes issue #15907)
Reported by: alecdavis
Patches: 
      cdr_congestion.diff.txt uploaded by alecdavis (license #5546)

Review: https://reviewboard.asterisk.org/r/454/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@329835 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/cdr.h

@@ -58,6 +58,7 @@ enum {
 	AST_CDR_FAILED   = (1 << 1),
 	AST_CDR_BUSY     = (1 << 2),
 	AST_CDR_ANSWERED = (1 << 3),
+	AST_CDR_CONGESTION = (1 << 4),
 };
 
 /*!
@@ -266,6 +267,15 @@ void ast_cdr_answer(struct ast_cdr *cdr);
  */
 extern void ast_cdr_noanswer(struct ast_cdr *cdr);
 
+/*!
+ * \brief A call was set to congestion
+ * \param cdr the cdr you wish to associate with the call
+ * Markst he channel disposition as "CONGESTION"
+ * Will skip CDR's in chain with ANS_LOCK bit set. (see
+ * forkCDR() application
+ */
+extern void ast_cdr_congestion(struct ast_cdr *cdr);
+
 /*!
  * \brief Busy a call
  * \param cdr the cdr you wish to associate with the call