Using access() is a time-of-check/time-of-use race condition.  It is
okay to use them to provide better error messages, but that is pretty
much it.

This is not one such case; on the other hand, access() *will* skip
unlink() for a non-existent path, so ignore ENOENT return values from
the unlink() system call.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>