bundle: highlight misbehavior when --base does not match any revision

See next changeset for fix and details.

tests/test-bundle-r.t

@@ -140,6 +140,15 b' should fail'
   $ hg -R test bundle --base 2 --all test-bundle-all-2.hg
   ignoring --base because --all was specified
   9 changesets found
+  $ hg -R test bundle --base 3-3 -r tip test-base-match-nothing-with-dest.hg --config paths.default=$TESTTMP/test-3
+  searching for changes (known-bad-output !)
+  1 changesets found (known-bad-output !)
+  5 changesets found (missing-correct-output !)
+  $ hg -R test bundle --base 3-3 -r tip test-base-match-nothing-no-dest.hg
+  config error: default repository not configured! (known-bad-output !)
+  (see 'hg help config.paths') (known-bad-output !)
+  5 changesets found (missing-correct-output !)
+  [30]
   $ hg -R test bundle --base 3 -r tip test-bundle-should-fail.hg
   1 changesets found