modified the value of queryId from int to string (Azure#20767)

Author: Yiyao-MS

specification/mysql/resource-manager/Microsoft.DBforMySQL/preview/2018-06-01-privatepreview/examples/QueryTextsGet.json

@@ -4,7 +4,7 @@
     "subscriptionId": "ffffffff-ffff-ffff-ffff-ffffffffffff",
     "resourceGroupName": "testResourceGroupName",
     "serverName": "testServerName",
-    "queryId": 1
+    "queryId": "1"
   },
   "responses": {
     "200": {

specification/mysql/resource-manager/Microsoft.DBforMySQL/stable/2018-06-01/examples/QueryTextsGet.json

@@ -4,7 +4,7 @@
     "subscriptionId": "ffffffff-ffff-ffff-ffff-ffffffffffff",
     "resourceGroupName": "testResourceGroupName",
     "serverName": "testServerName",
-    "queryId": 1
+    "queryId": "1"
   },
   "responses": {
     "200": {