c++ client: remove unnecessary code

1. GetTableSchema() was implemented using its own RPC instead of a much
   simpler call to SyncLeaderMasterRpc(). An RPC is attractive for
   asynchronous use, but since it's never used that way, let's just switch
   over to SyncLeaderMasterRpc().
2. KuduTable::Open() was issuing both GetTableSchema() and
   GetTableLocations() RPCs. It's not clear why we're doing the latter; the
   response is completely ignored. So let's stop doing that.

My main motivation is to remove fragile error-handling and retry logic which
has been duplicated all over the client.

Change-Id: Idda2cc15bc6224df992bfe2eec287c0222adced0
Reviewed-on: http://gerrit.cloudera.org:8080/3809
Tested-by: Kudu Jenkins
Reviewed-by: Alexey Serbin <aserbin@cloudera.com>
Reviewed-by: Todd Lipcon <todd@apache.org>
4 files changed