[TESTS] stats: real time monitoring script for unix socket.

[TESTS] stats: real time monitoring script for unix socket.

Julien Antony and Matthieu Huguet of Prizee provided this convenient
script to monitor activity via the unix socket. It requires presence
of the "socat" utility. Example of usage :

lb1:/home/scripts# ./stats_haproxy.sh -s prizee_media,FRONTEND
189 session/s (avg: 189 )       1040 concurrent sessions
182 session/s (avg: 185 )       1022 concurrent sessions
164 session/s (avg: 178 )       1015 concurrent sessions
175 session/s (avg: 177 )       1015 concurrent sessions
226 session/s (avg: 187 )       1031 concurrent sessions
252 session/s (avg: 198 )       1056 concurrent sessions
273 session/s (avg: 208 )       1072 concurrent sessions
268 session/s (avg: 216 )       1080 concurrent sessions
271 session/s (avg: 222 )       1131 concurrent sessions
241 session/s (avg: 224 )       1128 concurrent sessions
215 session/s (avg: 223 )       1136 concurrent sessions
206 session/s (avg: 221 )       1140 concurrent sessions