Move scm.py to lib/

It belongs there.

Change-Id: I286b50c43c587c39557fc508175efbd4b0f51d51
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4289680
Reviewed-by: Joanna Wang <jojwang@chromium.org>
Commit-Queue: Josip Sokcevic <sokcevic@chromium.org>
diff --git a/git_cl.py b/git_cl.py
index 51a5708..3fc3354 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -45,9 +45,7 @@
 import owners_client
 import owners_finder
 import presubmit_canned_checks
-import presubmit_support
 import rustfmt
-import scm
 import setup_color
 import split_cl
 import subcommand
@@ -55,7 +53,7 @@
 import swift_format
 import watchlists
 
-from lib import utils
+from lib import change, scm, utils
 from third_party import six
 from six.moves import urllib
 
@@ -3315,8 +3313,8 @@
       separator = []  # No need for separator if there are no gerrit_footers.
 
     prev_line = top_lines[-1] if top_lines else ''
-    if (not presubmit_support.Change.TAG_LINE_RE.match(prev_line) or
-        not presubmit_support.Change.TAG_LINE_RE.match(line)):
+    if (not change.Change.TAG_LINE_RE.match(prev_line)
+        or not change.Change.TAG_LINE_RE.match(line)):
       top_lines.append('')
     top_lines.append(line)
     self._description_lines = top_lines + separator + gerrit_footers