Instead of checking device ids, try rename first and in case of EXDEV,

fallback to copy.

From rename(2) on Linux: Linux permits a file system to be mounted at multiple
points, but  rename()  does  not  work  across  different  mount points, even
if the same file system is mounted on both.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@834019 13f79535-47bb-0310-9956-ffa450edef68