Validate the changes applied through the nodemgr and svcmgr set/unset…

… actions

Example:

$ ha1 set --kw fs#10.type=cni
aubergine.ha1           E fs#10.dev is mandatory
aubergine.ha1           E the change was not saved

lib/extconfig.py

@@ -1158,6 +1158,10 @@ def _write_cf(self, buff):
         with codecs.open(fpath, "w", "utf8") as ofile:
             ofile.write(buff)
             ofile.flush()
+        report = self._validate_config(fpath)
+        if report["errors"]:
+            os.unlink(fpath)
+            raise ex.excError("the change was not saved")
         shutil.move(fpath, self.paths.cf)
 
     def print_config_data(self, src_config=None, evaluate=False, impersonate=None):