Fix issue where files do not get deleted after emptying recycle bin

DeleteDirectory was receiving `\\media\\205276` as the path, and DirectoryExists was returning false for that.  Running the path through `this.FixPath()` seems to fix the issue.

Author: tomfulton

src/UmbracoFileSystemProviders.Azure/AzureFileSystem.cs

@@ -245,6 +245,8 @@ public void AddFile(string path, Stream stream)
         /// </param>
         public void DeleteDirectory(string path, bool recursive)
         {
+            path = this.FixPath(path);
+
             if (!this.DirectoryExists(path))
             {
                 return;