Additional PL/Python regression test expected file

plpython_subtransaction test needs a separate expected file
specifically for Python 2.5.

src/pl/plpython/expected/README

 Guide to alternative expected files:
 
-plpython_error_0.out		Python 2.4 and older
+plpython_error_0.out			Python 2.4 and older
 
-plpython_unicode.out		server encoding != SQL_ASCII and client encoding == UTF8; else ...
-plpython_unicode_0.out		server encoding != SQL_ASCII and client encoding != UTF8; else ...
-plpython_unicode_3.out		server encoding == SQL_ASCII
+plpython_unicode.out			server encoding != SQL_ASCII and client encoding == UTF8; else ...
+plpython_unicode_0.out			server encoding != SQL_ASCII and client encoding != UTF8; else ...
+plpython_unicode_3.out			server encoding == SQL_ASCII
 
-plpython_subtransaction_0.out	Python 2.5 and older (without with statement)
+plpython_subtransaction_0.out	Python 2.4 and older (without with statement)
+plpython_subtransaction_5.out	Python 2.5 (without with statement)
 
-plpython_types_3.out		Python 3.x
+plpython_types_3.out			Python 3.x
 
 Note: Building with Python 2.2 is supported, but there are no expected
 files for it (too much work to maintain).