Remove db only if command is available

debian/postrm

@@ -54,10 +54,15 @@ case "$1" in
         rm -rf ${gitlab_cache_path}
         rm -rf ${gitlab_pid_path}
         # Don't fail if user is already removed
-        gitlab_user=${gitlab_user:-gitlab}
+        if [ -z "${gitlab_user}" ]; then
+            # If gitlab_user variable is unset or empty, use "gitlab" as default.
+            gitlab_user=gitlab
+        fi
         id -u ${gitlab_user} && userdel -r ${gitlab_user}
         rm -rf ${gitlab_data_dir}
+        if [ -x /usr/bin/dropdb ]; then
             su ${gitlab_user} -c 'psql gitlab_production -c ""' && su postgres -c "dropdb gitlab_production"
+        fi
         rm -rf ${gitlab_ssl_path}
       fi