Fix linting issue

Author: jaapmarcus

install/upgrade/versions/1.9.2.sh

@@ -34,8 +34,8 @@ done
 # Update permissiosn /usr/local/hestia/data/sessions
 chown -R hestiaweb:hestiaweb /usr/local/hestia/data/sessions
 
-if [ -n $DB_PGA_ALIAS ]; then
-	if [ -n $DB_PMA_ALIAS ]; then
+if [ -n "$DB_PGA_ALIAS" ]; then
+	if [ -n "$DB_PMA_ALIAS" ]; then
 		if [ "$DB_PMA_ALIAS" == "$DB_PGA_ALIAS" ]; then
 			$BIN/v-change-sys-db-alias pga "phppgadmin"
 		fi