fix boundary condition in histogram code

git-svn-id: svn+ssh://svn.corp.yahoo.com/yahoo/yrl/labs/pnuts/code/logstore@674 8dad8b1f-cf64-0410-95b6-bcf113ffbcfe

logserver.cpp

@@ -607,6 +607,7 @@ int op_stat_histogram(pthread_data* data, size_t limit) {
 
 	if(count > limit) {
 		stride = count / (limit-1);
+		stride++;  // this way, we truncate the last bucket instead of occasionally creating a tiny last bucket.
 	} else {
 		stride = 1;
 	}