py3: don’t encode node.bin() argument

It accepts str and bytes.

hgext/git/gitutil.py

@@ -1,52 +1,50
 """utilities to assist in working with pygit2"""
 
 from mercurial.node import bin, hex, sha1nodeconstants
 
 from mercurial import pycompat
 
 pygit2_module = None
 
 
 def get_pygit2():
     global pygit2_module
     if pygit2_module is None:
         try:
             import pygit2 as pygit2_module
 
             pygit2_module.InvalidSpecError
         except (ImportError, AttributeError):
             pass
     return pygit2_module
 
 
 def pygit2_version():
     mod = get_pygit2()
     v = "N/A"
 
     if mod:
         try:
             v = mod.__version__
         except AttributeError:
             pass
 
     return b"(pygit2 %s)" % v.encode("utf-8")
 
 
 def togitnode(n):
     """Wrapper to convert a Mercurial binary node to a unicode hexlified node.
 
     pygit2 and sqlite both need nodes as strings, not bytes.
     """
     assert len(n) == 20
     return pycompat.sysstr(hex(n))
 
 
 def fromgitnode(n):
     """Opposite of togitnode."""
     assert len(n) == 40
-    if pycompat.ispy3:
-        return bin(n.encode('ascii'))
     return bin(n)
 
 
 nullgit = togitnode(sha1nodeconstants.nullid)