Auto-login support for the pnfs-objects protocol

I'm happy to submit the auto-login support to pnfs-objects protocol. Please see individual patches for explanations.

It was heavily tested and performs very well.

Submitted, as usual, a patch to pnfsd-exofs that enables this in the pnfs Server Then follows a modest patch to the pnfs-obj client layout-driver. And last a patch to the nfs-utils package with a script that executes the login.

We currently only support the iscsi://ip_addr:ip_port URI protocol. But other are easy to add by modifying the script, as the Kernel part is just a transparent pass through between the Server and the osd_login script.

Benny: As the editor of the STD please review and confirm

List of Patches:
[PATCH 1/4] pnfsd-exofs: Add autologin support to exofs

This patch is for Benny's pnfsd tree. Thanks

[PATCH 2/4] pnfs-obj: Remove unused variable from objlayout_get_deviceinfo().

Trond: This is not important just something found when coding.

[PATCH 3/4] pnfs-obj: autologin: Add support for protocol autologin

Trond: If at all possible to make the merge window with this one It would be great. Thanks.

[PATCH 4/4] osd_login: Add autologin script for objlayoutdriver.

Steve D: This patch is for you. Thanks a million man, it made the complete code Kernel and user-mode 1/7 the size Cheers

Thanks
Sachin & Boaz