hg: update top-level script to use modern import conventions

hg

@@ -1,45 +1,47 b''
 #!/usr/bin/env python
 #
 # mercurial - scalable distributed SCM
 #
 # Copyright 2005-2007 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
+from __future__ import absolute_import
 
 import os
 import sys
 
 if os.environ.get('HGUNICODEPEDANTRY', False):
     try:
         reload(sys)
         sys.setdefaultencoding("undefined")
     except NameError:
         pass
 
 libdir = '@LIBDIR@'
 
 if libdir != '@' 'LIBDIR' '@':
     if not os.path.isabs(libdir):
         libdir = os.path.join(os.path.dirname(os.path.realpath(__file__)),
                               libdir)
         libdir = os.path.abspath(libdir)
     sys.path.insert(0, libdir)
 
 # enable importing on demand to reduce startup time
 try:
     if sys.version_info[0] < 3 or sys.version_info >= (3, 6):
         import hgdemandimport; hgdemandimport.enable()
 except ImportError:
     sys.stderr.write("abort: couldn't find mercurial libraries in [%s]\n" %
                      ' '.join(sys.path))
     sys.stderr.write("(check your install and PYTHONPATH)\n")
     sys.exit(-1)
 
-import mercurial.util
-import mercurial.dispatch
-
+from mercurial import (
+    dispatch,
+    util,
+)
 for fp in (sys.stdin, sys.stdout, sys.stderr):
-    mercurial.util.setbinary(fp)
+    util.setbinary(fp)
 
-mercurial.dispatch.run()
+dispatch.run()