Changed module-specific upgrade API, not backward compatible. The API has been simplified which means more has to be done by the programmer.

* In summary, a user registers an upgrade callback per module. The callback is called at startup if the module is added, has been removed or if the revision on file is different from the one in the system.
  * The register function has removed `from` and `rev` parameters: `upgrade_callback_register(h, cb, namespace, arg)`
  * The callback function has a new `op` parameter with possible values: `XML_FLAG_ADD`, `XML_FLAG_CHANGE` or `XML_FLAG_CHANGE`: `clicon_upgrade_cb(h, xn, ns, op, from, to, arg, cbret)`

lib/src/clixon_xml_changelog.c

@@ -356,6 +356,7 @@ changelog_iterate(clicon_handle h,
  * @param[in]  h       Clicon handle 
  * @param[in]  xt      Top-level XML tree to be updated (includes other ns as well)
  * @param[in]  namespace Namespace of module (for info)
+ * @param[in]  op      One of XML_FLAG_ADD, _DEL, _CHANGE
  * @param[in]  from    From revision on the form YYYYMMDD
  * @param[in]  to      To revision on the form YYYYMMDD (0 not in system)
  * @param[in]  arg     User argument given at rpc_callback_register() 
@@ -367,12 +368,13 @@ changelog_iterate(clicon_handle h,
  */
 int
 xml_changelog_upgrade(clicon_handle h,       
-		       cxobj        *xt,      
-		       char         *namespace,
-		       uint32_t      from,
-		       uint32_t      to,
-		       void         *arg,     
-		       cbuf         *cbret)
+		      cxobj        *xt,      
+		      char         *namespace,
+		      uint16_t      op,
+		      uint32_t      from,
+		      uint32_t      to,
+		      void         *arg,     
+		      cbuf         *cbret)
 {
     int        retval = -1;
     cxobj     *xchlog; /* changelog */