Fix validation errors when producing documentation using default build script

The awk script parses out the first instance of the DOCUMENTATION tag that it
finds within a file.  If a file did not previously have a DOCUMENTATION tag
but received one due to it having an AMI event, then the XML fragment
associated with the AMI event was erroneously placed in the resulting XML
file.  Without the python scripts, these XML fragments will not validate.

This patch adds DOCUMENTATION tags at the top of those files that did
not previously have them to prevent the awk script from pulling AMI event
documentation.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@369910 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/sig_analog.c

@@ -46,6 +46,9 @@
 
 #include "sig_analog.h"
 
+/*** DOCUMENTATION
+ ***/
+
 /*! \note
  * Define if you want to check the hook state for an FXO (FXS signalled) interface
  * before dialing on it.  Certain FXO interfaces always think they're out of