Update ssrs_migration.rss with more robust features

Added function to create folder if target does not contain folder.
Added helper function to use relative path for linking data source which is helpful in scenarios where data source does not live in the same directory as report file.

samples/features/reporting-services/ssrs-migration-rss/ssrs_migration.rss

@@ -223,7 +223,16 @@ Sub Main()
 
 	Console.ReadLine()
 	
-	
+	' Create destination folder if not present
+	Try 
+		RsSnk.CreateFolder(SnkFolder.Substring(1), "/", Nothing)
+	Catch ex As Exception
+		If (ex.Message.Contains("Microsoft.ReportingServices.Diagnostics.Utilities.ItemAlreadyExistsException"))
+			Console.WriteLine("Folder already exists.")
+		Else 
+			Console.WriteLine(ex.Message + Environment.NewLine)
+		End If
+	End Try
 
 	Try
 		'Roles & Policies
@@ -604,7 +613,7 @@ Sub RelinkItemReferences(snkItem As CatalogItem, srcItem As CatalogItem)
 			Dim type As String = RsSrc.GetItemType(srcRef.Reference)
 			Dim snkRef As ItemReference = New ItemReference
 			snkRef.Name = srcRef.Name
-			snkRef.Reference = GetSnkFilename(GetSnkPath(srcRef.Reference), type)
+			snkRef.Reference = GetSnkFilename(GetSnkPathRef(srcRef.Reference), type)
 
 			snkReferences.Add(snkRef)
 		Next
@@ -923,6 +932,12 @@ End Sub
 '''''''''''''' Helper Functions '''''''''''''''''''''''
 '''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
+'Helper function to link snk reference with relative paths
+Function GetSnkPathRef(srcPath As String) As String
+	Dim snkPath = srcPath.Remove(0, srcSiteUrl.LastIndexOf("/"))
+	Return snkPath
+End Function
+		
 'Helper function to construct correctly formatted path
 Function GetSnkPath(srcPath As String) As String
 	If Not SrcIsNative Then