testing/provisioner: fix code for InstallDeps
deploy: use Provisioner.InstallDeps instead of App.InstallDeps

I'm trying to clean App interface.
provision/juju: pass the Provisioner parameter to deploy.Git
provision/lxc: pass the Provisioner parameter to deploy.Git
provision: remove InstallDeps method from App
repository: remove file doc.go
deploy: bring clone and pull functions from repository package
repository: remove deploy related functions

Someday I will kill this package :-)
provision: remove Command method from App interface
provision/juju: fix deploy related test
provision/lxc: fix deploy related test
provision/lxc: remove commented test