git: a little pycompat.bytestring() love to make this code work in py3

Differential Revision: https://phab.mercurial-scm.org/D5765

contrib/python3-whitelist

@@ -116,6 +116,7 b' test-convert-cvs.t'
 test-convert-cvsnt-mergepoints.t
 test-convert-datesort.t
 test-convert-filemap.t
+test-convert-git.t
 test-convert-hg-sink.t
 test-convert-hg-source.t
 test-convert-hg-startrev.t

hgext/convert/git.py

@@ -13,6 +13,7 b' from mercurial import ('
     config,
     error,
     node as nodemod,
+    pycompat,
 )
 
 from . import (
@@ -175,7 +176,8 b' class convert_git(common.converter_sourc'
         self.catfilepipe[0].flush()
         info = self.catfilepipe[1].readline().split()
         if info[1] != ftype:
-            raise error.Abort(_('cannot read %r object at %s') % (ftype, rev))
+            raise error.Abort(_('cannot read %r object at %s') % (
+                pycompat.bytestr(ftype), rev))
         size = int(info[2])
         data = self.catfilepipe[1].read(size)
         if len(data) < size:
@@ -294,7 +296,7 b' class convert_git(common.converter_sourc'
             if not entry:
                 if not l.startswith(':'):
                     continue
-                entry = l.split()
+                entry = tuple(pycompat.bytestr(p) for p in l.split())
                 continue
             f = l
             if entry[4][0] == 'C':