43.0-2: do not touch global git config

PKGBUILD

@@ -4,7 +4,7 @@
 
 pkgname=gnome-shell
 pkgver=43.0
-pkgrel=1
+pkgrel=2
 epoch=1
 pkgdesc="Next generation desktop shell"
 url="https://wiki.gnome.org/Projects/GnomeShell"
@@ -38,10 +38,9 @@ pkgver() {
 prepare() {
   cd gnome-shell
 
-  git config --global protocol.file.allow always
   git submodule init
   git submodule set-url subprojects/gvc "$srcdir/libgnome-volume-control"
-  git submodule update
+  git -c protocol.file.allow=always submodule update
 }
 
 build() {