fix of arc-infosys-ldap init scripts when building with --prefix
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This merge request is automatically copied from !641 (merged) orginally made by @floridop
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## fix of arc-infosys-ldap init scripts when building with --prefix
Description
ldap subsystem will not search for arc.conf in the same place as a-rex.
I added some code that makes the scripts behave exactly like the a-rex scripts to be sure they use the same arc.conf file.