...it leads to better handling of the failure downstream, if e.g. this is an
attempt to copy a file from the presets to an existing file of a previously
partly generated UserInstallation, and the presets and the UserInstallation are
on different drives and rename(3) fails with EXDEV.  (Without this fix, removing
the UserInstallation's registrymodifications.xcu caused restarting soffice to
fail with "User installation could not be completed" in this case; regression
introduced with 6edbcc1b "cid#1242936 handle
rename failure.")

Change-Id: I409698c4e2e6cc6ccd8b2be80a393c9657b5125d