[MERGE] Don't retrieve the tree if log is called on the root.

[Jelmer Vernooij]

This patch optimizes the case when "bzr log" is called on the root of
a branch. At the moment, Bazaar opens the tree to find out the file id
to track in this case, when actually all history is required. 

This saves *some* time when running "bzr log
http://bazaar-vcs.org/bzr/bzr.dev" (31s -> 27s in an unscientific measurement),
and in particular when running "bzr log" on svn branches (2.18m -> 2.00m on 
vala).

Cheers,

Jelmer
-- 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: bzr-dev-4297.patch
Type: text/x-diff
Size: 2169 bytes
Desc: not available
Url : https://lists.ubuntu.com/archives/bazaar/attachments/20090417/ee940003/attachment.bin 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 315 bytes
Desc: Digital signature
Url : https://lists.ubuntu.com/archives/bazaar/attachments/20090417/ee940003/attachment.pgp