Cleaning up yamllint warnings

Cleaning up yamllint warnings

yamllint output:
build/baremetal-environment.yaml
  1:1       warning  missing document start "---"  (document-start)

build/opnfv-environment.yaml
  6:3       warning  comment not indented like content  (comments-indentation)
  14:4      warning  missing starting space in comment  (comments)
  123:1     warning  comment not indented like content  (comments-indentation)
  128:1     warning  comment not indented like content  (comments-indentation)
  156:1     warning  comment not indented like content  (comments-indentation)

config/deploy/os-odl-fdio-dvr-ha.yaml
  1:1       warning  missing document start "---"  (document-start)

config/deploy/os-odl-fdio-dvr-noha.yaml
  1:1       warning  missing document start "---"  (document-start)

config/network/network_settings_v6.yaml
  225:6     warning  missing starting space in comment  (comments)

Change-Id: I3985ce0b6740ce4694b5d75b477cb03c3dc49c28
Signed-off-by: Dan Radez <dradez@redhat.com>