Add VNF callback for ERROR.indication

Created a function nr_error_ind_cb for the VNF that takes a received ERROR.indication and shows some details regarding the reported error from the PNF, since up until now it was not handled and treated as an unknown message.
Proper error handling procedure not created, only shows that the error occurred.

nfapi/open-nFAPI/vnf/public_inc/nfapi_vnf_interface.h

@@ -294,7 +294,25 @@ typedef struct nfapi_vnf_config
 	 */
 	int (*start_resp)(nfapi_vnf_config_t* config, int p5_idx, nfapi_start_response_t* resp);
 	int (*nr_start_resp)(nfapi_vnf_config_t* config, int p5_idx, nfapi_nr_start_response_scf_t* resp);
-	
+
+	/*! A callback for the ERROR.indication
+	 *  \param config A pointer to the vnf configuration
+	 *  \param p5_idx The p5 index used to indicate a particular pnf p5 connection
+	 *  \param ind A data structure for the decoded ERROR.indication This will
+	 *              have been allocated on the stack.
+	 *  \return not currently used.
+	 *
+	 *  The ERROR.indication contains a reported error from the PNF, often signifying that a message has been sent too late
+	 *
+	 *
+	 *  The ind may contain pointers to dynamically allocated sub structures
+	 *  such as the vendor_extension. The dynamically allocated structure will
+	 *  be deallocated on return. If the client wishes to 'keep' the structures
+	 *  then the substructure pointers should be set to 0 and then the client should
+	 *  use the codec_config.deallocate function to release it at a future point
+	 */
+	int (*nr_error_ind)(nfapi_vnf_config_t* config, int p5_idx, nfapi_nr_error_indication_scf_t* ind);
+
 	/*! A callback for the STOP.resp
      *  \param config A pointer to the vnf configuration
 	 *  \param p5_idx The p5 index used to indicate a particular pnf p5 connection