message: [travis] Install Cabal library
  CI builds using GHC 7.6.3 will fail since appropriate Cabal library is missing
  This change makes sure to install Cabal
  Closes
diff: @@ -63,7 +63,7 @@ before_install:
  - if [ "$BOND_LANG" == "cs" ]; then travis_retry nuget install NUnit.Runners -version 2.6.4; fi
  - export PATH=/opt/cabal/1.22/bin:/opt/ghc/${BOND_GHC_VERSION#?}/bin:$PATH
  - cabal update
  - - cabal install happy
  + - cabal install happy Cabal
  before_script:
  # restore nuget packages for solution
  