finish build_target_lib.get_default_sysroot_path migration

This allows us to drop the build_target_lib import from cros_build_lib.

BUG=chromium:1170007
TEST=CQ passes

Change-Id: Icf01d140baa482014acfca800a57db7bb1bdc934
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2810800
Reviewed-by: Sergey Frolov <sfrolov@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_extract_deps.py b/scripts/cros_extract_deps.py
index 6f31cc3..5fa7695 100644
--- a/scripts/cros_extract_deps.py
+++ b/scripts/cros_extract_deps.py
@@ -15,6 +15,7 @@
 
 from chromite.lib.depgraph import DepGraphGenerator
 
+from chromite.lib import build_target_lib
 from chromite.lib import commandline
 from chromite.lib import cros_build_lib
 from chromite.lib import cros_logging as logging
@@ -310,7 +311,8 @@
 def main(argv):
   opts = ParseArgs(argv)
 
-  sysroot = opts.sysroot or cros_build_lib.GetSysroot(opts.board)
+  sysroot = (opts.sysroot or
+             build_target_lib.get_default_sysroot_path(opts.board))
   deps_list, _ = ExtractDeps(sysroot, opts.pkgs, opts.format)
 
   pformat.json(deps_list,