do not upgrade gana to master on bootstrap (see #6839)

bootstrap

@@ -8,13 +8,11 @@ if ! git --version >/dev/null; then
 fi
 
 
-git submodule update --init
+echo "$0: Updating submodules"
+echo | git submodule update --init
 
 ./contrib/gana-update.sh
 
-
-./contrib/gana.sh
-
 # This is more portable than `which' but comes with
 # the caveat of not(?) properly working on busybox's ash:
 existence()

contrib/gana.sh

@@ -6,3 +6,5 @@ set -eu
 cd contrib/gana
 git pull origin master
 cd ../..
+
+exec ./contrib/gana-update.sh