lock_ref_sha1_basic(): on SCLD_VANISHED, retry
lock_ref_sha1_basic(): on SCLD_VANISHED, retry

If safe_create_leading_directories() fails because a file along the
path unexpectedly vanished, try again (up to 3 times).

This can occur if another process is deleting directories at the same
time as we are trying to make them.  For example, "git pack-refs
--all" tries to delete the loose refs and any empty directories that
are left behind.  If a pack-refs process is running, then it might
delete a directory that we need to put a new loose reference in.

If safe_create_leading_directories() thinks this might have happened,
then take its advice and try again (maximum three attempts).

Signed-off-by: Michael Haggerty <c24c152f145c57791e809b126db9e61bd1c1782d@alum.mit.edu>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git