[SPARK-6179][SQL] Add token for "SHOW PRINCIPALS role_name" and "SHOW...

[SPARK-6179][SQL] Add token for "SHOW PRINCIPALS role_name" and "SHOW TRANSACTIONS" and "SHOW COMPACTIONS"

[SHOW PRINCIPALS role_name]
Lists all roles and users who belong to this role.
Only the admin role has privilege for this.

[SHOW COMPACTIONS]
It returns a list of all tables and partitions currently being compacted or scheduled for compaction when Hive transactions are being used.

[SHOW TRANSACTIONS]
It is for use by administrators when Hive transactions are being used. It returns a list of all currently open and aborted transactions in the system.

Author: DoingDone9 <799203320@qq.com>
Author: Zhongshuai Pei <799203320@qq.com>
Author: Xu Tingjun <xutingjun@huawei.com>

Closes #4902 from DoingDone9/SHOW_PRINCIPALS and squashes the following commits:

4add42f [Zhongshuai Pei] for test
311f806 [Zhongshuai Pei] for test
0c7550a [DoingDone9] Update HiveQl.scala
c8aeb1c [Xu Tingjun] aa
802261c [DoingDone9] Merge pull request #7 from apache/master
d00303b [DoingDone9] Merge pull request #6 from apache/master
98b134f [DoingDone9] Merge pull request #5 from apache/master
161cae3 [DoingDone9] Merge pull request #4 from apache/master
c87e8b6 [DoingDone9] Merge pull request #3 from apache/master
cb1852d [DoingDone9] Merge pull request #2 from apache/master
c3f046f [DoingDone9] Merge pull request #1 from apache/master

sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveQl.scala

@@ -113,13 +113,16 @@ private[hive] object HiveQl {
     
     "TOK_REVOKE",
     
+    "TOK_SHOW_COMPACTIONS",
     "TOK_SHOW_CREATETABLE",
     "TOK_SHOW_GRANT",
     "TOK_SHOW_ROLE_GRANT",
+    "TOK_SHOW_ROLE_PRINCIPALS",
     "TOK_SHOW_ROLES",
     "TOK_SHOW_SET_ROLE",
     "TOK_SHOW_TABLESTATUS",
     "TOK_SHOW_TBLPROPERTIES",
+    "TOK_SHOW_TRANSACTIONS",
     "TOK_SHOWCOLUMNS",
     "TOK_SHOWDATABASES",
     "TOK_SHOWFUNCTIONS",