HdrHistogram_c: update from 0.9.12 to 0.9.13 (#311)
HdrHistogram_c: update from 0.9.12 to 0.9.13 (#311)

Signed-off-by: Otto van der Schaaf <f82e1104fcd8bfffc72e7185709f7902b0b97ebf@we-amp.com>
envoyproxy/nighthawk,envoyproxy/nighthawk,envoyproxy/nighthawk,envoyproxy/nighthawk