res_ari_playback: Add missing 404 error response for GET and DELETE.

(closes issue ASTERISK-22722)
Reported by: Richard Mudgett
........

Merged revisions 402139 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@402140 65c4cc65-6c06-0410-ace0-fbb531ad65f3

rest-api/api-docs/playback.json

@@ -25,6 +25,12 @@
 							"allowMultiple": false,
 							"dataType": "string"
 						}
+					],
+					"errorResponses": [
+						{
+							"code": 404,
+							"reason": "The playback cannot be found"
+						}
 					]
 				},
 				{
@@ -41,6 +47,12 @@
 							"allowMultiple": false,
 							"dataType": "string"
 						}
+					],
+					"errorResponses": [
+						{
+							"code": 404,
+							"reason": "The playback cannot be found"
+						}
 					]
 				}
 			]