description:
replica: fix mkfile script installation

The $SCRIPTS were added to $TARG, which complicates the all rule, as 
each script's object file must be suppressed.
Fix by removing $SCRIPTS from $TARG, removing the script object file 
suppression rule, and overriding the install rule.

The script bin install rule assumes that only one script install is 
called at a time. Valid calls like 'mk -a /$objtype/replica/changes 
/$objtype/replica/pull' will fail.
Fix by adding a for loop.

Remove the unused $UPDATE variable.

Thanks,
Amavect