make_chroot: fix make.conf.user generation

Make sure we don't expand variables that we intend to be literals.

BUG=chromium:1059101
TEST=None

Change-Id: Ic7564f734b1ff4a3f317dd2deb1b38ae7f70b1b3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2089970
Reviewed-by: Dana Goyette <dgoyette@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/sdk_lib/make_chroot.sh b/sdk_lib/make_chroot.sh
index a0bbcc8..1e5fa09 100755
--- a/sdk_lib/make_chroot.sh
+++ b/sdk_lib/make_chroot.sh
@@ -250,7 +250,7 @@
      "${FLAGS_chroot}/etc/portage/make.profile"
 
    # Create make.conf.user .
-   cat <<EOF > "${FLAGS_chroot}"/etc/make.conf.user
+   cat <<\EOF > "${FLAGS_chroot}"/etc/make.conf.user
 # This file is useful for doing global (chroot and all board) changes.
 # Tweak emerge settings, ebuild env, etc...
 #