Ensure that all options start at their default

Before loading options, set them all to their default values. This way, if
anything goes wrong while loading, we fall back to the default. This is
especially relevant for options like fonts whose default is determined at
runtime.

client/options.cpp

@@ -4246,6 +4246,11 @@ void options_load()
   const char *const prefix = "client";
   const char *str;
 
+  // Ensure all options start with their default value
+  for (auto &option : client_options) {
+    option_reset(OPTION(&option));
+  }
+
   name = get_last_option_file_name(&allow_digital_boolean);
   if (!name) {
     qInfo(_("Didn't find the option file. Creating a new one."));