Remove git submodule utility functions

We no longer use submodules

jupyter_notebook/submodule.py

@@ -1,90 +0,0 @@
-"""utilities for checking submodule status"""
-
-# Copyright (c) Jupyter Development Team.
-# Distributed under the terms of the Modified BSD License.
-
-import os
-import subprocess
-import sys
-
-pjoin = os.path.join
-
-
-def repo_parent():
-    """return IPython's parent (i.e. root if run from git)"""
-    import jupyter_notebook
-    return os.path.abspath(os.path.dirname(jupyter_notebook.__file__))
-
-def submodule_path(root):
-    """return submodule path relative to root"""
-    return [
-        pjoin(root, 'jupyter_notebook', 'static', 'components'),
-    ]
-
-def is_repo(d):
-    """is d a git repo?"""
-    if not os.path.exists(pjoin(d, '.git')):
-        return False
-    proc = subprocess.Popen('git status',
-                            stdout=subprocess.PIPE,
-                            stderr=subprocess.PIPE,
-                            shell=True,
-                            cwd=d,
-    )
-    status, _ = proc.communicate()
-    return status == 0
-
-def check_submodule_status(root=None):
-    """check submodule status
-
-    Has three return values:
-
-    'missing' - submodules are absent
-    'unclean' - submodules have unstaged changes
-    'clean' - all submodules are up to date
-    """
-
-    if hasattr(sys, "frozen"):
-        # frozen via py2exe or similar, don't bother
-        return 'clean'
-
-    if not root:
-        root = repo_parent()
-    
-    if not is_repo(root):
-        # not in git, assume clean
-        return 'clean'
-
-    submodules = submodule_path(root)
-
-    for submodule in submodules:
-        if not os.path.exists(submodule):
-            return 'missing'
-    
-    # Popen can't handle unicode cwd on Windows Python 2
-    if sys.platform == 'win32' and sys.version_info[0] < 3 \
-        and not isinstance(root, bytes):
-        root = root.encode(sys.getfilesystemencoding() or 'ascii')
-    # check with git submodule status
-    proc = subprocess.Popen('git submodule status',
-                            stdout=subprocess.PIPE,
-                            stderr=subprocess.PIPE,
-                            shell=True,
-                            cwd=root,
-    )
-    status, _ = proc.communicate()
-    status = status.decode("ascii", "replace")
-
-    for line in status.splitlines():
-        if line.startswith('-'):
-            return 'missing'
-        elif line.startswith('+'):
-            return 'unclean'
-
-    return 'clean'
-
-def update_submodules(repo_dir):
-    """update submodules in a repo"""
-    subprocess.check_call("git submodule init", cwd=repo_dir, shell=True)
-    subprocess.check_call("git submodule update --recursive", cwd=repo_dir, shell=True)
-