* Made a separate Clixon datastore XML/JSON top-level symbol

* Replaces the hardcoded "config" keyword.
  * Implemented by a compile-time option called `DATASTORE_TOP_SYMBOL` option in clixon_custom.h
* Tests: added endtest to all tests. Removed all premature exits if BE=0

test/test_restconf_ssl_certs.sh

@@ -166,9 +166,9 @@ EOF
 function testrun()
 {
     cat <<EOF > $dir/startup_db
-    <config>
+    <${DATASTORE_TOP}>
        $RULES
-    </config>
+    </${DATASTORE_TOP}>
 EOF
     if [ $BE -ne 0 ]; then
 	new "kill old backend"