msi: Don't fail if we can't remove an existing install file.

dlls/msi/files.c

@@ -355,8 +355,12 @@ static INT_PTR cabinet_notify(FDINOTIFICATIONTYPE fdint, PFDINOTIFICATION pfdin)
                               NULL, CREATE_ALWAYS, attrs, NULL );
         if ( handle == INVALID_HANDLE_VALUE )
         {
+            if ( GetFileAttributesW( f->TargetPath ) != INVALID_FILE_ATTRIBUTES )
+                f->state = msifs_installed;
+            else
                 ERR("failed to create %s (error %d)\n",
                     debugstr_w( f->TargetPath ), GetLastError() );
+
             return 0;
         }