Manually applying https://github.com/Activiti/Activiti/pull/454, as we've moved to asciidoc
Merge branch 'master' of https://github.com/Activiti/Activiti

# By karnahla
# Via Tijs Rademakers (2) and karnahla (1)
* 'master' of https://github.com/Activiti/Activiti:
  changed behavior on process-deploy: check only existing start-message-subscriptions