Import 03be6db0e1: Renderable is nullptr segfaults fixes (by Maki)

This is an automated proposal to look at a commit made by Maki and import it into Overte

Commit:	03be6db0e11124a8af7137e0e896e0a9d0f7be8c
Author:	Maki
Date:	Thu, 19 Mar 2020 00:01

Renderable is nullptr segfaults fixes

Stats:

Filename	Stats	Lines	Added	Removed	Lines in blame
libraries/entities-renderer/src/EntityTreeRenderer.cpp		6	3	3	⚠ 0
1 files	-	6	3	3	0

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