Remove no longer used compat imports

Author: Harmon758

git/index/fun.py

@@ -19,7 +19,6 @@
     force_text,
     force_bytes,
     is_posix,
-    safe_encode,
     safe_decode,
 )
 from git.exc import (

git/test/test_repo.py

@@ -36,10 +36,6 @@
     BadName,
     GitCommandError
 )
-from git.compat import (
-    is_win,
-    win_encode,
-)
 from git.exc import (
     BadObject,
 )

git/util.py

@@ -32,7 +32,6 @@
 from git.compat import is_win
 import os.path as osp
 
-from .compat import defenc
 from .exc import InvalidGitRepositoryError