pylint: Fix use-list-literal

Pylint 2.10 introduced new checker use-list-literal:
> Added use-list-literal: Emitted when list() is called with no
  arguments instead of using []

https://pylint.pycqa.org/en/latest/whatsnew/changelog.html#what-s-new-in-pylint-2-10-0
pylint-dev/pylint#4365

Fixes: freeipa#244
Signed-off-by: Stanislav Levin <slev@altlinux.org>

src/ipahealthcheck/ipa/idns.py

@@ -63,8 +63,8 @@ def check(self):
         txt_rec = {}
         srv_rec = {}
         uri_rec = {}
-        a_rec = list()
-        aaaa_rec = list()
+        a_rec = []
+        aaaa_rec = []
 
         for name, node in base_records.items():
             for rdataset in node: