[json-c] enable dataflow config (#1632). (#3265)
[json-c] enable dataflow config (#1632). (#3265)

Should work based on https://pantheon.corp.google.com/logs/viewer?resource=build%2Fbuild_id%2F3fc8371d-951a-4003-9ce5-97d4adaf449c&project=oss-fuzz&minLogLevel=0&expandAll=false&timestamp=2020-01-21T22:54:26.943000000Z&customFacets=&limitCustomFacetWidth=true&dateRangeEnd=2020-01-21T22:54:25.085Z&interval=PT1H&dateRangeUnbound=backwardInTime&scrollTimestamp=2020-01-21T18:50:28.370948047Z, double checking with Travis.
skia-dev/oss-fuzz,FeliciaLim/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,FeliciaLim/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,google/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,FeliciaLim/oss-fuzz,FeliciaLim/oss-fuzz,robertswiecki/oss-fuzz,FeliciaLim/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz