After tablet level metrics is supported, the http metrics API may response
a very large body when a BE holds a large number of tablets, and cause heavy
network traffic.
This patch introduce http content compression to reduce network traffic.
1. No one can set root password expect for root user itself
2. NODE_PRIV cannot be granted.
3. ADMIN_PRIV and GRANT_PRIV can only be granted or revoked on *.*
4. No one can modifly privs of default role 'operator' and 'admin'.
5. No user can be granted to role 'operator'.
Fixed: the running load limit should not be applied to replay logic. It will cause replay or loading image fail.
Changed: optimize the problem of too many directories under mini load directory.
Fixed: missing password and auth check when handling mini load request in Frontend.
Fixed: DomainResolver should start after Frontends transfer to a certain ROLE, not in Catalog construction methods.
Fixed: a stupid bug that no one can set password for root user... fix it: only root user can set password for root.
Fixed: read null data twice
When reading data with a null value, in some cases, the same data will be read twice by the storage engine,
resulting in a wrong result.The reason for this problem is that when splitting,
and the start key is the minimum value, the data with null is read.
Fixed: add a flag to prevent DomainResovler thread start twice.
Fixed: fixed a mem leak of using ByteBuf when parsing auth info of http request.
Fixed: add a new config 'disable_hadoop_load', default is false, set to true to disable hadoop load.
Changed: add detail error msg of submitting hadoop load job in show load result.
Fixed: Backend process should be crashed if failed to saving header.
Added: exposure backend info to user when encounter error on Backend. for debugging it more convenient.
Fixed: Should remove fd from map when inputstream or outputstream is closed in Broker process.
Fixed: Change all files' LF to unix format.
Internal commit id: merge from dfcd0aca18eed9ff99d188eb3d01c60d419be1b8
1. Implement Backend http server using libevent instead of mongoose.
2. Remove Old Hypertable rpc framework, use brpc instead.
3. Change rpc from FE to BE to brpc.
4. Fs broker support HDFS HA.
5. add more metrics to monitor.
6. Lots of bug fixed.
