Catch a CGenErr by const reference rather than by value

This fixes alerts from LGTM.

Signed-off-by: Stefan Weil <sw@weilnetz.de>

src/clientdlg.cpp

@@ -1079,7 +1079,7 @@ void CClientDlg::Connect ( const QString& strSelectedAddress,
             }
         }
 
-        catch ( CGenErr generr )
+        catch ( const CGenErr& generr )
         {
             // show error message and return the function
             QMessageBox::critical ( this, APP_NAME, generr.GetErrorText(), "Close", nullptr );

src/main.cpp

@@ -706,7 +706,7 @@ int main ( int argc, char** argv )
         }
     }
 
-    catch ( CGenErr generr )
+    catch ( const CGenErr& generr )
     {
         // show generic error
 #ifndef HEADLESS