1. solved the previous delayed unit test file size is too large (1.7G+) and the unit test link time is too long problem problems
2. Unify all unit tests into one file to significantly reduce unit test execution time to less than 3 mins
3. temporarily disable stream_load_test.cpp, metrics_action_test.cpp, load_channel_mgr_test.cpp because it will re-implement part of the code and affect other tests
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
