Merge pull request Azure#6 from TimeSeriesInsights/partionKeyProperty-ModelingAsString

changing modelAsString for partitionKeyPRoperties

Author: ravikumarsureshbabu

specification/timeseriesinsights/resource-manager/Microsoft.TimeSeriesInsights/stable/2017-11-15/timeseriesinsights.json

@@ -1396,7 +1396,7 @@
           ],
           "x-ms-enum": {
             "name": "PropertyType",
-            "modelAsString": false
+            "modelAsString": true
           }
         }
       },