Fix region clean up, when view destroy

[ftdebugger]

Region with "replaceElement" setting don't restore region element, when view was destroyed by self. Because view element remove from DOM before destroy event fired. Listen before:destroy fix this problem.

[coveralls]

Coverage remained the same at 100.0% when pulling 1dd5754 on ftdebugger:next into b5e1066 on marionettejs:next.

[rafde]

hmm... should https://github.com/marionettejs/backbone.marionette/pull/3262/files#diff-b8da5292cb07ec757ac64e78ff5af5c1R67
be updated to 'before:destroy' instead of doing this?

[rafde]

I think this.view.destroy(); should do the event emitting instead in order to match a real scenario.

[paulfalgout]

👏 Good find.

@rafde I don't think before:destroy will work everywhere because empty checks if a view is destroyed.

However I think the easiest cheapest solution to this is to add view.on('before:destroy', this._restoreEl, this); to _replaceEl

https://jsfiddle.net/bbapmrsw/1/

I don't think clean up of this event will be necessary either as the events will be cleaned up. _restoreEl will be called twice, but will bail the second time at the isReplaced check.

[paulfalgout]

@ftdebugger any interest on revising this a bit?