depmod: prevent module dependency files missing during depmod invocation

depmod: prevent module dependency files missing during depmod invocation

depmod deletes the module dependency files before moving the temporary
files in their place. This results in user seeing no dependency files
while they are updated. Remove the unlink call. The rename call should
suffice to move the new file in place and unlink the old one. It should
also do both atomically so there is no window when no dependency file
exists.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>