Catch the right exception for config errors

This originally belonged to #15.

src/scdaq.cc

@@ -214,7 +214,7 @@ int main(int argc, char *argv[]) {
     //    utility::report_elapsed_time((tbb::tick_count::now() -
     //    mainStartTime).seconds());
     return retval;
-  } catch (std::exception &e) {
+  } catch (std::invalid_argument &e) {
     LOG(FATAL) << "Configuration invalid! Error text is \"" << e.what()
                << "\" Bailing out.";
     return EX_CONFIG;