admin-verify: expect a number of errors to be returned

It's the responsibility of the check to handle errors, we only care about
the total count to sum up the check's work.

We use `admin::verify -c dirstate` to test this path at least somewhat.

mercurial/admin_commands.py

@@ -47,4 +47,4 b' def admin_verify(ui, repo, **opts):'
         ui.status(_(b"running %s\n") % name)
         errors = func()
         if errors:
-            ui.warn(_(b"found %d errors\n") % len(errors))
+            ui.warn(_(b"found %d errors\n") % errors)

tests/test-verify.t

@@ -132,6 +132,16 b' Entire changelog and manifest log missin'
   dirstate inconsistent with current parent's manifest
   1 dirstate errors
   [1]
+
+We can check the dirstate in isolation
+  $ hg admin::verify -c dirstate
+  running 1 checks
+  running working-copy.dirstate
+  checking dirstate
+  warning: ignoring unknown working parent c5ddb05ab828!
+  file marked as tracked in p1 (000000000000) but not in manifest1
+  found 1 errors
+
   $ cp -R .hg/store-full/. .hg/store
 
 Entire changelog and filelog missing