update test for unrelated repo.

tests/test-unrelated-pull

@@ -16,4 +16,5 b' hg add b'
 hg commit -m "b" -u b -d "1000000 0"
 
 hg pull ../a
+hg pull -f ../a
 hg heads

tests/test-unrelated-pull.out

@@ -1,6 +1,9 b''
 pulling from ../a
 searching for changes
-warning: pulling from an unrelated repository!
+abort: repository is unrelated
+pulling from ../a
+searching for changes
+warning: repository is unrelated
 adding changesets
 adding manifests
 adding file changes