The helper function for summing statistic over the column family are
template function that infer the return type acording to the type of the
Init param.
In the API the return value should be int64_t, passing an integer would
cause a number wrap around.
A partial output from the nodetool cfstats after the fix
nodetool cfstats keyspace1
Keyspace: keyspace1
Read Count: 0
Read Latency: NaN ms.
Write Count: 4050000
Write Latency: 0.009178098765432099 ms.
Pending Flushes: 0
Table: standard1
SSTable count: 12
Space used (live): 1118617445
Space used (total): 23336562465
Fixes#682
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
b0856f7acf