Fixing bosh deployment instructions for vcloud

Instructed to refer to vsphere micro bosh deployment which is up-to-date. This aims to avoid duplication. Used sensible vm sizing for microbosh in micro_bosh-vcloud.yml.
Added a mention about http_proxy into deploying_micro_bosh.md
Merge pull request #272 from gberche-orange/cf-doc-fix

Fixing bosh deployment instructions for vcloud
PR #272