Code review comment for lp:~fwereade/juju-core/bootstrap-constraints-2

Reviewers: mp+153600_code.launchpad.net,

Message:
Please take a look.

Description:
cmd/juju: bootstrap accepts --constraints

...and passes them on to environs.Bootstrap, which passes them on to
Environ.Bootstrap. Only the dummy provider actually handles constraints
at the moment -- so we can test the bootstrap command -- all the others
will be implemented in followups.

https://code.launchpad.net/~fwereade/juju-core/bootstrap-constraints-2/+merge/153600

Requires:
https://code.launchpad.net/~fwereade/juju-core/bootstrap-constraints-1/+merge/153523

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/7610048/

Affected files:
   A [revision details]
   M cmd/builddb/main.go
   M cmd/juju/bootstrap.go
   M cmd/juju/bootstrap_test.go
   M environs/bootstrap.go
   M environs/bootstrap_test.go
   M environs/dummy/environs.go
   M environs/ec2/ec2.go
   M environs/ec2/local_test.go
   M environs/interface.go
   M environs/jujutest/livetests.go
   M environs/jujutest/tests.go
   M environs/open_test.go
   M environs/openstack/local_test.go
   M environs/openstack/provider.go
   M juju/apiconn_test.go
   M juju/conn_test.go
   M juju/testing/conn.go