Fix shellcheck warnings from code review

- Fix NCUSER typo -> NCDBUSER in nextcloud_update.sh
- Replace indirect exit code check with direct check in nextcloud_install_production.sh

Author: enoch85

nextcloud_install_production.sh

@@ -365,16 +365,15 @@ install_if_not postgresql
 # Create DB with proper permissions for Nextcloud 30+
 # PostgreSQL 15+ requires explicit schema permissions
 cd /tmp
-sudo -u postgres psql <<END
+if ! sudo -u postgres psql <<END
 CREATE USER $PGDB_USER WITH PASSWORD '$PGDB_PASS';
 CREATE DATABASE nextcloud_db WITH OWNER $PGDB_USER TEMPLATE template0 ENCODING 'UTF8';
 \c nextcloud_db
 GRANT CREATE ON SCHEMA public TO $PGDB_USER;
 GRANT ALL ON SCHEMA public TO $PGDB_USER;
 ALTER DATABASE nextcloud_db OWNER TO $PGDB_USER;
 END
-
-if [ $? -ne 0 ]; then
+then
     print_text_in_color "$IRed" "Failed to create PostgreSQL database with proper permissions!"
     print_text_in_color "$ICyan" "Please report this to $ISSUES"
     exit 1

nextcloud_update.sh

@@ -92,7 +92,7 @@ then
     ncdb
 
     # Check if we need to apply the fix (test if user can create tables)
-    if sudo -u postgres psql -d "$NCDB" -c "SELECT has_schema_privilege('$NCUSER', 'public', 'CREATE');" 2>/dev/null | grep -q "f"
+    if sudo -u postgres psql -d "$NCDB" -c "SELECT has_schema_privilege('$NCDBUSER', 'public', 'CREATE');" 2>/dev/null | grep -q "f"
     then
         print_text_in_color "$ICyan" "Applying PostgreSQL schema permission fix for Nextcloud 30+..."