Fix negative values reported for the number of dropped i/o requests.
Fix negative values reported for the number of dropped i/o
requests.

synety-jdebp/rtpproxy,synety-jdebp/rtpproxy,jevonearth/rtpproxy,jevonearth/rtpproxy,sippy/rtp_cluster,synety-jdebp/rtpproxy,sippy/rtpproxy,synety-jdebp/rtpproxy,sippy/rtpproxy,sippy/rtp_cluster,dsanders11/rtpproxy,dsanders11/rtpproxy,jevonearth/rtpproxy,dsanders11/rtpproxy,jevonearth/rtpproxy,sippy/rtpproxy