Fix return status of summary within impala shell

Follow up fix to IMPALA-1153. Ensure that the correct
CmdStatus is returned by the summary command. (ERROR for
invalid queries and SUCCESS even if summary is not available.)

Change-Id: Icf67164dc82f202ec15071541f6ed3b26e3ad7fb
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4089
Reviewed-by: Abdullah Yousufi <abdullah.yousufi@cloudera.com>
Tested-by: jenkins

shell/impala_shell.py

@@ -387,10 +387,10 @@ class ImpalaShell(cmd.Cmd):
       pass
     if summary is None:
       print_to_stderr("Could not retrieve summary for query.")
-      return True
+      return CmdStatus.ERROR
     if summary.nodes is None:
       print_to_stderr("Summary not available")
-      return True
+      return CmdStatus.SUCCESS
     output = []
     table = self.construct_table_header(["Operator", "#Hosts", "Avg Time", "Max Time",
                                            "#Rows", "Est. #Rows", "Peak Mem",

tests/shell/test_shell_commandline.py

@@ -258,7 +258,7 @@ class TestImpalaShell(object):
     assert "03:AGGREGATE" in result_set.stdout
 
     args = "-q 'summary;'"
-    result_set = run_impala_shell_cmd(args)
+    result_set = run_impala_shell_cmd(args, expect_success=False)
     assert "Could not retrieve summary for query" in result_set.stderr
 
     args = "-q 'show tables; summary;'"