Rename also in docker files

Signed-off-by: Christian König <ckoenig@posteo.de>

advanced/Scripts/piholeCheckout.sh

@@ -9,7 +9,7 @@
 # Please see LICENSE file for your rights under this license.
 
 readonly PI_HOLE_FILES_DIR="/etc/.pihole"
-PH_TEST="true"
+SKIP_INSTALL="true"
 source "${PI_HOLE_FILES_DIR}/automated install/basic-install.sh"
 
 # webInterfaceGitUrl set in basic-install.sh

advanced/Scripts/update.sh

@@ -17,7 +17,7 @@ readonly PI_HOLE_GIT_URL="https://github.com/pi-hole/pi-hole.git"
 readonly PI_HOLE_FILES_DIR="/etc/.pihole"
 
 # shellcheck disable=SC2034
-PH_TEST=true
+SKIP_INSTALL=true
 
 # when --check-only is passed to this script, it will not perform the actual update
 CHECK_ONLY=false