Update libglnx to get g_autoptr backports

Update submodule: libglnx

Closes: #1603
Approved by: jlebon

diff --git a/libglnx b/libglnx
index 03e16afa7f2cf7ce517b604035683fa0409f730c..e1a78cf2f5351d5394ccfb79f3f5a7b4917f73f3 160000 (submodule)
--- a/libglnx
+++ b/libglnx
@@ -1 +1 @@
-Subproject commit 03e16afa7f2cf7ce517b604035683fa0409f730c
+Subproject commit e1a78cf2f5351d5394ccfb79f3f5a7b4917f73f3