More verbose error and proper app name on configuration read error

Signed-off-by: Julius Härtl <jus@bitgrid.net>

src/gui/application.cpp

@@ -189,9 +189,9 @@ Application::Application(int &argc, char **argv)
                 nullptr,
                 tr("Error accessing the configuration file"),
                 tr("There was an error while accessing the configuration "
-                   "file at %1.")
+                   "file at %1. Please make sure the file can be accessed by your user.")
                     .arg(ConfigFile().configFile()),
-                tr("Quit Nextcloud"));
+                tr("Quit %1").arg(Theme::instance()->appNameGUI()));
             QTimer::singleShot(0, qApp, SLOT(quit()));
             return;
         }