Returning false here instead of dying is going to generate other errors. Places that use the `loadFromXML` method of the updater generally don't do something like this (which they should)

```php
if ($updater->loadFromXML($url))
{
    $updater->get('some_value', 'default');
}
```

You can see an example of what not to do here: https://github.com/dongilbert/joomla-cms/blob/staging/administrator/components/com_installer/models/install.php#L311-311

Line 312 is just assuming that it gets an object back from its call to `$updater->get()` which is actually kind of crazy, because if you return false from here as this pr suggests, then it's very possible that the requested value isn't present, in which case it will return the default value of false, and not an object. The method chaining there on that needs to be fixed up for this PR to be merged so that users aren't stuck with a different kind of error that might not be as "google-able" to discover the answer, know what I mean?

I'm sure there are other areas as well that are inadvertently depending on this `die` to occur so as to avoid other types of errors (an example of which I pointed out above), so I wouldn't merge that until those were looked at.

FWIW, I did a search for `loadFromXML`, and it's only used in 6 places total (not including the function definition).

```sh
administrator/components/com_installer/models/install.php
311:			$update->loadFromXML($url);

administrator/components/com_installer/models/languages.php
243:		$update->loadFromXML($remote_manifest);

administrator/components/com_installer/models/update.php
239:			$update->loadFromXML($instance->detailsurl);

administrator/components/com_joomlaupdate/models/default.php
164:		$update->loadFromXML($updateObject->detailsurl);

installation/model/languages.php
208:		$update->loadFromXML($remote_manifest);

libraries/joomla/updater/updater.php
204:		if ($update->loadFromXML($updaterow->details url))
```