tmt t lint should also try to cover adjust rules

Fix [issue#898](#898)

Signed-off-by: Vector Li <[email protected]>

tmt/base.py

@@ -289,7 +289,11 @@ def export(self, format_='yaml', keys=None):
     def lint_keys(self, additional_keys):
         """ Return list of invalid keys used, empty when all good """
         known_keys = additional_keys + self._keys
-        return [key for key in self.node.get().keys() if key not in known_keys]
+        input_keys = list(self.node.get().keys())
+        prop_adjust = self.node.get('adjust')
+        if prop_adjust is not None:
+            input_keys.extend([key for element in prop_adjust for key in element.keys()])
+        return [key for key in input_keys if key not in known_keys]
 
     def _lint_summary(self):
         """ Lint summary attribute """