tests: restore previous fix for date ambiguity in cvs test

017ab404e588 changed some sleeps after cvs update to sleeps before commit. I
don't know why that should work, but I have a machine where it doesn't work.
Commits regularly fails becuase cvs doesn't notice that a file has been
changed.

Restoring the previous sleep between the update and the edit makes cvs notice
the change.

tests/test-convert-cvs-detectmerge.t

@@ -54,6 +54,7 b' create two release branches'
 modify file1 on branch v1_0
 
   $ cvscall -Q update -rv1_0
+  $ sleep 1
   $ echo "change" >> file1
   $ cvsci -m"add text"
   cvs commit: Examining .