msi: Don't fail if the directory already exists in MsiCreateAndVerifyInstallerDirectory.
[wine] / dlls / wintab.dll16 /
drwxr-xr-x   ..
-rw-r--r-- 114 Makefile.in
-rw-r--r-- 14216 wintab.c
-rw-r--r-- 2622 wintab.dll16.spec