[BOOTDATA][SETUPLIB][REACTOS] INF support fixes.

- BOOTDATA: Use standard INF signature string, so that they can be
  opened successfully using ReactOS' or Windows' setupapi.dll with
  the INF_STYLE_WIN4 style.

- SETUPLIB: Use the correct INF_STYLE_* INF styles in SpInfOpenInfFile() calls.

- REACTOS : Switch thread locale to user-specified LocaleId when calling
  SetupOpenInfFileW(), so that the correct localized strings are used.

base/setup/lib/install.c

@@ -783,7 +783,7 @@ PrepareFileCopy(
 
         InfHandle = SpInfOpenInfFile(PathBuffer,
                                      NULL,
-                                     INF_STYLE_OLDNT, // INF_STYLE_WIN4,
+                                     INF_STYLE_WIN4,
                                      pSetupData->LanguageId,
                                      &ErrorLine);
         }