simplified the directory reader a little bit

* we do not need to make a second allocation for the systemFilePath
* as systemFilePath is never null, there is no need to check for that case.

src/common/filesystem/source/file_directory.cpp

@@ -131,7 +131,7 @@ int FDirectory::AddDirectory(const char *dirpath, LumpFilterInfo* filter, FileSy
 					}
 					// for internal access we use the normalized form of the relative path.
 					Entries[count].FileName = NormalizeFileName(entry.FilePathRel.c_str());
-					Entries[count].SystemFilePath = stringpool->Strdup(Entries[count].FileName);
+					Entries[count].SystemFilePath = FileName;
 					Entries[count].CompressedSize = Entries[count].Length = entry.Length;
 					Entries[count].Flags = RESFF_FULLPATH;
 					Entries[count].ResourceID = -1;
@@ -170,9 +170,7 @@ FileReader FDirectory::GetEntryReader(uint32_t entry, int readertype, int)
 	if (entry < NumLumps)
 	{
 		std::string fn = mBasePath;
-		fn += Entries[entry].SystemFilePath ?
-			Entries[entry].SystemFilePath :
-			Entries[entry].FileName;
+		fn += Entries[entry].SystemFilePath;
 		fr.OpenFile(fn.c_str());
 		if (readertype == READER_CACHED)
 		{