The original intent was to indicate success or failure of loading
settings. However, it's not clear what success or failure means
because it is legitimate to not have a user- or site-settings file, so
indicating failure if one of these cannot be loaded is not really
accurate. Moreover, the return value wasn't used by the caller.

In addition, there was a bug in the previous implementation. If the
user settings weren't loaded, the site settings wouldn't be loaded
either. Now this method no longer returns any boolean value.

Change-Id: I039fc39aec3866e0d5b349fa43fc8f5c0d648d2a