Update git submodules

Update git submodules

* Update docs/submodules/vid.git from branch 'casablanca'
  to ff6340c554ee6e257a53f09b7c8b286d2ea197b7
  - New VID certificate valid until: March 12, 2020

    Alias name: vid@vid.onap.org
    Owner: C=US, O=ONAP, OU=OSAAF, OU=vid@vid.onap.org, EMAILADDRESS=, CN=vid
    Issuer: CN=intermediateCA_9, OU=OSAAF, O=ONAP, C=US
    Valid from: Tue Mar 12 15:26:01 GMT 2019
         until: Thu Mar 12 15:26:01 GMT 2020

    SubjectAlternativeName [
      DNSName: vid
      DNSName: vid.api.simpledemo.onap.org
      DNSName: vid.onap
    ]

    (cherry picked from commit 9514224ee2a39fbb8102f0b137c3c9d320f7f16e)

    Issue-ID: VID-446
    Change-Id: I3aa02e8d4e840568d2dd74d442e4ab9c9e041399
    Signed-off-by: Ittay Stern <ittay.stern@att.com>