Add file-count for Transmission RPC

(cherry picked from commit 23c741fd001582fa363c2723eff9facd3091618b)

src/NzbDrone.Core/Download/Clients/Transmission/TransmissionProxy.cs

@@ -221,6 +221,7 @@ namespace NzbDrone.Core.Download.Clients.Transmission
                 "seedIdleLimit",
                 "seedIdleMode",
                 "fileCount",
+                "file-count",
                 "labels"
             };
 

src/NzbDrone.Core/Download/Clients/Transmission/TransmissionTorrent.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Newtonsoft.Json;
 
 namespace NzbDrone.Core.Download.Clients.Transmission
 {
@@ -24,6 +25,12 @@ namespace NzbDrone.Core.Download.Clients.Transmission
         public int SeedRatioMode { get; set; }
         public long SeedIdleLimit { get; set; }
         public int SeedIdleMode { get; set; }
-        public int FileCount { get; set; }
+        public int FileCount => TransmissionFileCount ?? VuzeFileCount ?? 0;
+
+        [JsonProperty(PropertyName = "file-count")]
+        public int? TransmissionFileCount { get; set; }
+
+        [JsonProperty(PropertyName = "fileCount")]
+        public int? VuzeFileCount { get; set; }
     }
 }