CALF: minor LMMS-specific updates

Silence a compiler warning introduced by custom changes and fix a
possible compile failure by including another header file in a header
file that we cleared before.

plugins/ladspa_effect/calf/src/calf/osctlnet.h

@@ -0,0 +1,2 @@
+#include <calf/osctl.h>
+

plugins/ladspa_effect/calf/src/giface.cpp

@@ -209,10 +209,10 @@ const char *calf_plugins::load_gui_xml(const std::string &plugin_id)
         return strdup(calf_utils::load_file((std::string(PKGLIBDIR) + "/gui-" + plugin_id + ".xml").c_str()).c_str());
     }
     catch(file_exception e)
+#endif
     {
         return NULL;
     }
-#endif
 }
 
 bool calf_plugins::check_for_message_context_ports(const parameter_properties *parameters, int count)