[PATCH 1 of 3] demandimport: remove support for Python < 2.5

[Gregory Szorc]

# HG changeset patch
# User Gregory Szorc <gregory.szorc at gmail.com>
# Date 1439071287 25200
#      Sat Aug 08 15:01:27 2015 -0700
# Node ID 4c1a937f7837d4dab00d1ab555ae6f53c2739eaf
# Parent  e5891ade62b1a4dba017fd9d7b8cacb4ab200014
demandimport: remove support for Python < 2.5

The removed code was to support an __import__ function that doesn't
support the "level" argument. This argument was added in Python 2.5,
which we no longer support.

diff --git a/mercurial/demandimport.py b/mercurial/demandimport.py
--- a/mercurial/demandimport.py
+++ b/mercurial/demandimport.py
@@ -36,20 +36,13 @@ except ImportError:
 _origimport = __import__
 
 nothing = object()
 
-try:
-    # Python 3 doesn't have relative imports nor level -1.
-    level = -1
-    if sys.version_info[0] >= 3:
-        level = 0
-    _origimport(builtins.__name__, {}, {}, None, level)
-except TypeError: # no level argument
-    def _import(name, globals, locals, fromlist, level):
-        "call _origimport with no level argument"
-        return _origimport(name, globals, locals, fromlist)
-else:
-    _import = _origimport
+# Python 3 doesn't have relative imports nor level -1.
+level = -1
+if sys.version_info[0] >= 3:
+    level = 0
+_import = _origimport
 
 def _hgextimport(importfunc, name, globals, *args):
     try:
         return importfunc(name, globals, *args)