Fixes for autosave managed NFS mounts

[JJL772]

These changes allow for autosave to manage mounts where the exported path is not the same as the mount point.

Tested on: RTEMS-mvme3100 (RTEMS 4.10.2)

The original behavior is retained.

[anjohnson]

I'm not the maintainer of this module but I can and will approve the PR to be run.

The thing that concerns me slightly about it is the printing of messages when a remount occurs and succeeds. The previous code appears to have been silent when successful, so users who were monitoring the IOC console might think that this change has caused additional NFS issues, or they might just not want to know when it worked properly. I understand the desire to be able to enable such messages for debugging and monitoring, but I wonder if the maintainers might prefer to keep the old behavior, maybe condition the prints on some debug or verbosity setting?

[JJL772]

Good catch, I didn't even notice the duplicated printfs. I'm going to leave the "Successfully remounted ..." message alone, as it's a good indicator that autosave was conducting a remount.