#769 headnode/image uid/gid mismatch

[Bernard Li]

Currently OSCAR blindly syncs (overwrite) the compute
node's/image's passwd/group files based on what's on
the headnode, this has the potential problem of making
the gid/uid of certain users out of sync.

For example if a RPM is installed on the headnode which
creates a user, but this RPM is not installed on the
compute node, having the headnode's passwd/group file
overwrite the compute node's would cause certain
file/directory ownership mismatch.

The first known "victim" of this issue is the PVM
package. See bug #1368604 "/opt/pvm3 directory
ownership on image" for more detail.