Merge "res_fax: add FAXMODE variable" into 13

diff --cc CHANGES
index ca216ec4f4f93c44aa7cfb311d1212c7cff58953,fb8e681e24a11d7a5d378b001d8569a61f5d9145..63b814c21c2c3fcb0b323e6062f65a24dacd5224
--- 1/CHANGES
--- 2/CHANGES
+++ b/CHANGES
@@@ -12,10 -12,13 +12,15 @@@
  --- Functionality changes from Asterisk 13.9.0 to Asterisk 13.10.0 -----------
  ------------------------------------------------------------------------------
  
+ res_fax
+ ------------------
+  * Added FAXMODE variable to let dialplan know what fax transport was used.
+    FAXMODE variable is set to either "audio" or "T38".
+ 
  res_pjsip
  ------------------
 + * Added new status Updated to AMI event ContactStatus on update registration
 +
   * Added "reg_server" to contacts.
     If the Asterisk system name is set in asterisk.conf, it will be stored
     into the "reg_server" field in the ps_contacts table to facilitate