analytics: don't verify config from repo

Otherwise this will raise an exception from analytics worker:
```
dvc config cache.type sometypo
```
But running that same command with `--system` or `--global` flag outside
of repo won't raise that.

Also need to better handle ConfigObjError, but that is a separate issue.

dvc/analytics.py

@@ -219,10 +219,10 @@ class Analytics(object):
 
         try:
             dvc_dir = Repo.find_dvc_dir()
-            config = Config(dvc_dir)
         except NotDvcRepoError:
-            config = Config(validate=False)
-        return config
+            dvc_dir = None
+
+        return Config(dvc_dir, validate=False)
 
     @staticmethod
     def is_enabled(cmd=None):

tests/unit/test_analytics.py

@@ -0,0 +1,14 @@
+from dvc.analytics import Analytics
+from dvc.config import Config
+from dvc.repo import NotDvcRepoError
+
+
+def test_broken_config(mocker, dvc_repo):
+    Config(dvc_repo.dvc_dir, validate=False).set("cache", "type", "unknown")
+
+    assert Analytics._get_current_config()
+
+    with mocker.patch(
+        "dvc.repo.Repo.find_dvc_dir", side_effect=NotDvcRepoError(".")
+    ):
+        assert Analytics._get_current_config()