verify: fix "missing revlog!" errors for revlog format v0 and add test With revlog format v0 the .d files are empty if the only revision stored is an empty file. Since Mercurial can no longer create format v0 repositories, but still use it, add a script which creates a repository with a single empty file. This can be used in other tests if wanted.

--- a/tests/test-verify	Thu Sep 02 22:38:12 2010 +0200
+++ b/tests/test-verify	Sun Sep 05 22:32:11 2010 +0200
@@ -48,4 +48,12 @@
 echo % verify
 hg verify
 
+cd ..
+
+echo % test revlog format 0
+
+"$TESTDIR/revlog-formatv0.py"
+cd formatv0
+hg verify
+
 exit 0