- Fix double free in destructor of caps plugin (bnc#842420)

NOTE: _link of ladspa-devel isn't done intentionally due to the historical
reason. ladspa-devel was a separate repo in the past and indepdendent
from ladspa main package, because ladspa-devel is nothing but a single
header file, and triggering rebuilds of other packages due to each ladspa
plugin change makes no sense.
But during the migration to OBS, ladspa-devel repo was merged into ladspa,
and it looks as if this is bound together.