Set the RPATH in all cases

Description

The cmsgemos online software heavily depends on the xDAQ and Cactus libraries, in particular their external Boost dependency. While the RPATH is set in the local installation to simplify testing, it is not the case for global installations, in particular in the RPM packages. Considering the dangers of setting globally the LD_LIBRARY_PATH environment variable pointing to custom library builds, the cmsgemos tools user-friendliness is severely impacted.

Possible fixes

Set the RPATH regardless of the installation path or method. The xDAQ and Cactus libraries are anyhow installed in well-known locations and the search path can always be overridden via the LD_LIBRARY_PATH environment variables if required.