[scm] Clean up unused functions

This change removes some dead code from back in the SVN days. `GetCasedPath()`[1] and `GenFakeDiff()`[2] were a part of the SVN class from when scm.py used to support two scm. `only_int()` was used within `AssertVersion()` which was removed[3]. I could not find any usage for `ValidateEmail()` even within the old commits[4].

[1] https://codereview.chromium.org/538009
[2] https://codereview.chromium.org/1965001
[3] https://crrev.com/c/2116938
[4] https://codereview.chromium.org/501166

Bug: 1475776
Change-Id: I730f0d994d8027bd67587fd16ad1e502bdfb94fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5279813
Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>
Commit-Queue: Aravind Vasudevan <aravindvasudev@google.com>

scm.py

@@ -4,12 +4,9 @@
 """SCM-specific utility classes."""
 
 from collections import defaultdict
-import glob
-import io
 import os
 import platform
 import re
-import sys
 from typing import Mapping, List
 
 import gclient_utils
@@ -24,53 +21,6 @@ VERSIONED_DIR = 1
 VERSIONED_SUBMODULE = 2
 
 
-def ValidateEmail(email):
-    return (re.match(r"^[a-zA-Z0-9._%\-+]+@[a-zA-Z0-9._%-]+.[a-zA-Z]{2,6}$",
-                     email) is not None)
-
-
-def GetCasedPath(path):
-    """Elcheapos way to get the real path case on Windows."""
-    if sys.platform.startswith('win') and os.path.exists(path):
-        # Reconstruct the path.
-        path = os.path.abspath(path)
-        paths = path.split('\\')
-        for i in range(len(paths)):
-            if i == 0:
-                # Skip drive letter.
-                continue
-            subpath = '\\'.join(paths[:i + 1])
-            prev = len('\\'.join(paths[:i]))
-            # glob.glob will return the cased path for the last item only. This
-            # is why we are calling it in a loop. Extract the data we want and
-            # put it back into the list.
-            paths[i] = glob.glob(subpath + '*')[0][prev + 1:len(subpath)]
-        path = '\\'.join(paths)
-    return path
-
-
-def GenFakeDiff(filename):
-    """Generates a fake diff from a file."""
-    file_content = gclient_utils.FileRead(filename, 'rb').splitlines(True)
-    filename = filename.replace(os.sep, '/')
-    nb_lines = len(file_content)
-    # We need to use / since patch on unix will fail otherwise.
-    data = io.StringIO()
-    data.write("Index: %s\n" % filename)
-    data.write('=' * 67 + '\n')
-    # Note: Should we use /dev/null instead?
-    data.write("--- %s\n" % filename)
-    data.write("+++ %s\n" % filename)
-    data.write("@@ -0,0 +1,%d @@\n" % nb_lines)
-    # Prepend '+' to every lines.
-    for line in file_content:
-        data.write('+')
-        data.write(line)
-    result = data.getvalue()
-    data.close()
-    return result
-
-
 def determine_scm(root):
     """Similar to upload.py's version but much simpler.
 
@@ -89,13 +39,6 @@ def determine_scm(root):
         return None
 
 
-def only_int(val):
-    if val.isdigit():
-        return int(val)
-
-    return 0
-
-
 class GIT(object):
     current_version = None
     rev_parse_cache = {}