LADSPA: fix bug in setting parameter descriptions
LADSPA: fix bug in setting parameter descriptions

The parameter names were not properly set for LADSPA plugin
parameters. E.g. in  output of 'map-ladspa-list' ECI command,
the description field was always empty for LADSPA plugins.

Bug reported by Jeremy Salwen.

jeremysalwen/Ecasound-LV2,jeremysalwen/Ecasound-LV2,jeremysalwen/Ecasound-LV2,jeremysalwen/Ecasound-LV2,jeremysalwen/Ecasound-LV2