[MERGE][#90049] Don't require a working tree in cmd_annotate.

[Andrew Bennetts]

Andrew Bennetts has voted approve.
Status is now: Semi-approved
Comment:
This looks fine to me.

You have also changed it to lock_read the working tree rather than the 
branch (when there is a working tree).  That seems to make sense, 
though.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C1198954632.6703.1.camel%40nemo%3E