Code review comment for lp:~thumper/juju-core/common-api-env-watcher

The attempt to merge lp:~thumper/juju-core/common-api-env-watcher into lp:juju-core failed. Below is the output from the failed tests.

# launchpad.net/juju-core/state/api/deployer
state/api/deployer/deployer.go:24: undefined: common
state/api/deployer/deployer.go:24: not enough arguments to return
# launchpad.net/juju-core/state/api/common
state/api/common/life.go:14: undefined: Caller
# launchpad.net/juju-core/state/api/machiner
state/api/machiner/machiner.go:23: undefined: common
state/api/machiner/machiner.go:23: not enough arguments to return
# launchpad.net/juju-core/state/api/uniter
state/api/uniter/uniter.go:29: undefined: common
state/api/uniter/uniter.go:29: not enough arguments to return