misc/create_inode: simplify logic in scandir()

misc/create_inode: simplify logic in scandir()

The control flow in scandir() (only used on Windows) confuses gcc into
thinking that *name_list is not always set on success, which causes a
-Wmaybe-uninitialized warning in __populate_fs().  As far as I can tell
it's a false positive; however, avoid it by cleanly separating the
success and failure cases in scandir().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>