LT-22318 LIFT import fails when in root directory (#551)

Fixed problem with getting path when lift file was in a root directory instead of a folder.

Change-Id: I414296077a2f88ef1aaf9352240e43c08c81900b

Author: KenZook

Src/LexText/LexTextControls/LiftImportDlg.cs

@@ -244,7 +244,7 @@ private object ImportLIFT(IThreadedProgress progressDlg, params object[] paramet
 							File.Move(filePath, Path.Combine(sWritingSystems, file));
 					}
 				}
-				var sTempOrigFile = Path.Combine(sLIFTtempFolder, sOrigFile.Substring(sLIFTfolder.Length + 1));
+				var sTempOrigFile = Path.Combine(sLIFTtempFolder, Path.GetFileName(sOrigFile));
 				string sFilename;
 				//Do a LIFT Migration to the current version of LIFT if it is needed.
 				bool fMigrationNeeded = Migrator.IsMigrationNeeded(sTempOrigFile);