prevent whitespace splitting

acme.sh

@@ -2412,7 +2412,7 @@ _getdeployconf() {
     return 0 # do nothing
   fi
   _saved="$(_readdomainconf "SAVED_$_rac_key")"
-  eval $_rac_key="$_saved"
+  eval $_rac_key=\$_saved
   export $_rac_key
 }