Changes related to allowing seperate 'fs' (file server) node.

Entailed new instructions for manual setup as well as integration into
elabinelab framework.  First, the manual path:

setup.txt, setup-boss.txt, setup-ops.txt and new setup-fs.txt:
    Updated to reflect potential for separate fs node.  The org here
    is a little dicey and could be confusing with ops+fs vs. ops and fs.
    Has not been field tested yet.

*/GNUmakefile.in: new fs-install target.

configure, configure.in, defs-*:
    Somewhat unrelated, make min uid/gid to use be a defs setting.
    Also add config of fs-install.in script.

boss-install.in, ops-install.in and new fs-install.in:
    Handle distinct fs node.  If you have one, fs-install is run before
    ops-install.  All scripts rely on the defs file settings of FSNODE
    and USERNODE to determine if the fs node is seperate.

utils/checkquota.in:
    Just return "ok" if quotas are not used (i.e., if defs file FS_WITH_QUOTA
    string is null.

install/ports/emulab-fs:
    Meta port for fs node specific stuff.  Also a patch for the samba port
    Makefile so it doesn't drag in CUPs, etc.  Note that the current samba
    port Makefile has this change, I am just backporting to our version.

Elabinelab specific changes:

elabinelab-withfs.ns:
    NS fragment used in conjunction with
	tb-elab-in-elab-topology "withfs"
    to setup inner-elab with fs node.

elabinelab.ns:
    The hard work on the boss side.  Recognize seperate-fs config and handle
    running of rc.mkelab on that node.  fs setup happens before ops setup.

rc.mkelab:
    The hard work on the client side.  Recognize FsNode setup as well as
    differentiate ops+fs from ops setup.

Related stuff either not part of the repo or checked in previously:
    emulab-fs package