Improve PL/Python elog output

When the elog functions (plpy.info etc.) get a single argument, just print
that argument instead of printing the single-member tuple like ('foo',).

src/pl/plpython/expected/plpython_import.out

@@ -51,7 +51,7 @@ return "sha hash of " + plain + " is " + digest.hexdigest()'
 -- import python modules
 --
 SELECT import_fail();
-NOTICE:  ('import socket failed -- No module named foosocket',)
+NOTICE:  import socket failed -- No module named foosocket
 CONTEXT:  PL/Python function "import_fail"
     import_fail     
 --------------------

src/pl/plpython/expected/plpython_spi.out

@@ -125,7 +125,7 @@ else:
    return None
 $$ LANGUAGE plpythonu;
 SELECT result_nrows_test();
-INFO:  (True,)
+INFO:  True
 CONTEXT:  PL/Python function "result_nrows_test"
  result_nrows_test 
 -------------------

src/pl/plpython/expected/plpython_test.out

@@ -32,21 +32,24 @@ plpy.debug('debug')
 plpy.log('log')
 plpy.info('info')
 plpy.info(37)
+plpy.info()
 plpy.info('info', 37, [1, 2, 3])
 plpy.notice('notice')
 plpy.warning('warning')
 plpy.error('error')
 $$ LANGUAGE plpythonu;
 SELECT elog_test();
-INFO:  ('info',)
+INFO:  info
 CONTEXT:  PL/Python function "elog_test"
-INFO:  (37,)
+INFO:  37
+CONTEXT:  PL/Python function "elog_test"
+INFO:  ()
 CONTEXT:  PL/Python function "elog_test"
 INFO:  ('info', 37, [1, 2, 3])
 CONTEXT:  PL/Python function "elog_test"
-NOTICE:  ('notice',)
+NOTICE:  notice
 CONTEXT:  PL/Python function "elog_test"
-WARNING:  ('warning',)
+WARNING:  warning
 CONTEXT:  PL/Python function "elog_test"
-ERROR:  ('error',)
+ERROR:  error
 CONTEXT:  PL/Python function "elog_test"

src/pl/plpython/plpython.c

 /**********************************************************************
  * plpython.c - python as a procedural language for PostgreSQL
  *
- *	$PostgreSQL: pgsql/src/pl/plpython/plpython.c,v 1.131 2009/11/03 09:35:18 petere Exp $
+ *	$PostgreSQL: pgsql/src/pl/plpython/plpython.c,v 1.132 2009/11/03 11:05:02 petere Exp $
  *
  *********************************************************************
  */
@@ -3080,7 +3080,16 @@ PLy_output(volatile int level, PyObject *self, PyObject *args)
 	char	   *volatile sv;
 	volatile MemoryContext oldcontext;
 
-	so = PyObject_Str(args);
+	if (PyTuple_Size(args) == 1)
+	{
+		/* Treat single argument specially to avoid undesirable
+		 * ('tuple',) decoration. */
+		PyObject *o;
+		PyArg_UnpackTuple(args, "plpy.elog", 1, 1, &o);
+		so = PyObject_Str(o);
+	}
+	else
+		so = PyObject_Str(args);
 	if (so == NULL || ((sv = PyString_AsString(so)) == NULL))
 	{
 		level = ERROR;

src/pl/plpython/sql/plpython_test.sql

@@ -27,6 +27,7 @@ plpy.debug('debug')
 plpy.log('log')
 plpy.info('info')
 plpy.info(37)
+plpy.info()
 plpy.info('info', 37, [1, 2, 3])
 plpy.notice('notice')
 plpy.warning('warning')