Add check that shouldn't need to be checked

Somehow on tests, the temp folder would render itself unfindable, and thus made the program crash.

DATFromDir/DATFromDir.cs

@@ -95,8 +95,11 @@ namespace SabreTools
 				}
 
 				// Delete the temp directory
+				if (Directory.Exists(_tempDir))
+				{
 					Directory.Delete(_tempDir, true);
 				}
+			}
 
 			// Order the roms by name of parent, then name of rom
 			roms.Sort(delegate (Tuple<string, string, long, string> A, Tuple<string, string, long, string> B)