In Devstack environment, cloud-init can not work correctly, because
instance can not access metadata over ther network.
1. This patch will fix cloud-init error, user can use 'user_data'
in vnfd template.
2. Update missing plugin in Tacker (mistral, ceilometer) and
user_data in vnfd template for testing VNFFG function.
Change-Id: Ic2037aaf3e947e941b43d1ae06e475a712398c09
Closes-Bug: #1736627
eda624279f