Add writeId and stats fields in Partition

Delete and insert Hive ACID operations must update the writeId
of partitions as part of commit, and our hive_metastore.thrift doesn't
have writeId.  This commit adds that field as seen in the master hive
branch, as well as two optional statistics fields, isStatsCompliant
and colStats.

src/main/thrift/hive_metastore.thrift

@@ -443,7 +443,8 @@ struct Partition {
   6: StorageDescriptor   sd,
   7: map<string, string> parameters,
   8: optional PrincipalPrivilegeSet privileges,
-  9: optional string catName
+  9: optional string catName,
+  10: optional i64 writeId=-1
 }
 
 struct PartitionWithoutSD {