Merging postreleasefix/83 to master
Merging postreleasefix/83 to master

* postreleasefix/83:
  ensGA only exists if GA is initialised
  [ENSWEB-2020] If GA plugin is missing, this will break everything

muffato/public-plugins,Ensembl/public-plugins,muffato/public-plugins,Ensembl/public-plugins,muffato/public-plugins,muffato/public-plugins,Ensembl/public-plugins