Extract searching relevat files in utils function

This change introduces lib/ directory which will be used for classes
that are considered libraries and used by multiple executables.

Change-Id: I3da126778bf5ffdb28d7a3c2b966c85de08ba717
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4289679
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 3c8e4ac..d4d190d 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -55,6 +55,7 @@
 import swift_format
 import watchlists
 
+from lib import utils
 from third_party import six
 from six.moves import urllib
 
@@ -6131,7 +6132,6 @@
 
 
 def CMDversion(parser, args):
-  import utils
   print(utils.depot_tools_version())