Restore the ability of htdigest.exe to create files that contain

more than one user. On win32 we cannot system("copy") a file, while
it's open.

PR: PR 12910


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@98893 13f79535-47bb-0310-9956-ffa450edef68