Update collections-c that fixes segfault upstream.

.gitmodules

@@ -10,6 +10,5 @@
     path = ext/spookyhash
     url = https://github.com/centaurean/spookyhash.git
 [submodule "ext/collections-c"]
-    path = ext/collections-c
-    url = https://github.com/scossu/lsup-collections-c.git
-    branch = fix_iter_segfault
+	path = ext/collections-c
+	url = https://github.com/srdja/Collections-C.git

ext/collections-c

@@ -1 +1 @@
-Subproject commit 402d5fa7d29000a578dbaba425179d45115e7f10
+Subproject commit 719fd8c229b2fb369e9fc175fc97ad658108438c