[MERGE] Change the `bzr init-repo` default to --trees (#53483)

[John Arbash Meinel]

John Arbash Meinel has voted +1 (conditional).
Status is now: Approved
Comment:
I think it needs to be done slightly differently, but switching the 
default is good.

Probably we need a test which checks "bzr init-repo --trees" still 
works, since that would have shown that change broke it.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C20070202170420.GC6165%40larstiq.dyndns.org%3E