Return errors on disk full for file creation.

Core/FileSystems/VirtualDiscFileSystem.h

@@ -133,10 +133,12 @@ private:
 		u64 size;			// only used by lbn files
 
 		bool Open(std::string& basePath, std::string& fileName, FileAccess access) {
+			// Ignored, we're read only.
+			u32 err;
 			if (handler.IsValid()) {
 				return handler.Open(basePath, fileName, access);
 			} else {
-				return hFile.Open(basePath, fileName, access);
+				return hFile.Open(basePath, fileName, access, err);
 			}
 		}
 		size_t Read(u8 *data, s64 size) {