Add stat field missing in last commit

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@1070 d4fa192b-c00b-0410-8231-f00ffab90ce4

include/stat_field.h

@@ -27,6 +27,7 @@ MAC_STAT(n_wrk_failed,		uint64_t, "u", "N worker threads not created")
 MAC_STAT(n_wrk_max,		uint64_t, "u", "N worker threads limited")
 MAC_STAT(n_wrk_busy,		uint64_t, "u", "N busy worker threads")
 MAC_STAT(n_wrk_queue,		uint64_t, "u", "N queued work requests")
+MAC_STAT(n_wrk_overflow,	uint64_t, "u", "N overflowed work requests")
 
 MAC_STAT(n_expired,		uint64_t, "u", "N expired objects")
 MAC_STAT(n_deathrow,		uint64_t, "u", "N objects on deathrow")