Enhanced the "invalid line ... ignoring" listener error

Added the offending line to the error output, when otherwise skipping a mangled Metric line.

was:
invalid line received from client 10.113.2.37:42652, ignoring

now:
invalid line (server.lax.laxapp23.p7776.VL1  1349267164) received from client 10.113.2.37:42652, ignoring