build-all: drop unused opencollada pr622 patch

Last reference to this file was dropped in 7ae685dbf, though the ref was
pointing to `/patches/opencollada/pr622.patch`, so IIUC
`patches/pr622.patch` was never used.

(cherry picked from commit c013b9aca7)

nix/patches/pr622.patch

@@ -1,22 +0,0 @@
-From a0deb4ce8b43cf3c8b8c0a4225c6be5296446dbd Mon Sep 17 00:00:00 2001
-From: Adam Eri <adam.eri@blackmirror.media>
-Date: Tue, 3 Sep 2019 23:30:20 +0200
-Subject: [PATCH] Resolves compile error on macOS
-
-Resolves "no member named 'isnan' in namespace 'std'" on macOS
----
- GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp | 1 +
- 1 file changed, 1 insertion(+)
-
-diff --git a/GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp b/GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp
-index 1f9a3eef..dd6f5c59 100644
---- a/GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp
-+++ b/GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp
-@@ -10,6 +10,7 @@
- 
- #include "GeneratedSaxParserUtils.h"
- #include <math.h>
-+#include <cmath>
- #include <memory>
- #include <string.h>
- #include <limits>