msi: Don't fail if the directory already exists in MsiCreateAndVerifyInstallerDirectory.
[wine] / dlls / vmm.vxd /
drwxr-xr-x   ..
-rw-r--r-- 57 Makefile.in
-rw-r--r-- 17862 vmm.c
-rw-r--r-- 40 vmm.vxd.spec