ARI: Correct segfault with /variable calls are missing ?variable parameter.

Both /asterisk/variable and /channel/{channelId}/variable requires a
?variable parameter to be passed into the query. But we weren't checking
for the parameter being missing, which caused a segfault.

All calls now properly return 400 Bad Request errors when the parameter
is missing. The Swagger api-docs were updated accordingly.

(closes issue ASTERISK-22273)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@397306 65c4cc65-6c06-0410-ace0-fbb531ad65f3

rest-api/api-docs/asterisk.json

@@ -55,6 +55,12 @@
 							"allowMultiple": false,
 							"dataType": "string"
 						}
+					],
+					"errorResponses": [
+						{
+							"code": 400,
+							"reason": "Missing variable parameter."
+						}
 					]
 				},
 				{
@@ -79,6 +85,12 @@
 							"allowMultiple": false,
 							"dataType": "string"
 						}
+					],
+					"errorResponses": [
+						{
+							"code": 400,
+							"reason": "Missing variable parameter."
+						}
 					]
 				}
 			]

rest-api/api-docs/channels.json

@@ -753,6 +753,10 @@
 						}
 					],
 					"errorResponses": [
+						{
+							"code": 400,
+							"reason": "Missing variable parameter."
+						},
 						{
 							"code": 404,
 							"reason": "Channel not found"
@@ -795,6 +799,10 @@
 						}
 					],
 					"errorResponses": [
+						{
+							"code": 400,
+							"reason": "Missing variable parameter."
+						},
 						{
 							"code": 404,
 							"reason": "Channel not found"