build_target_util: Rename to build_target_lib.

Nitty name change. The module contains a class and is in lib, so
should be a _lib, not a _util.

BUG=chromium:1060351
TEST=run_tests

Change-Id: I539dc8e5288e71cc9408bc68861f20579ac70937
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2095746
Commit-Queue: Alex Klein <saklein@chromium.org>
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/setup_board.py b/scripts/setup_board.py
index adfa3e3..85eaecc 100644
--- a/scripts/setup_board.py
+++ b/scripts/setup_board.py
@@ -15,7 +15,7 @@
 
 import sys
 
-from chromite.lib import build_target_util
+from chromite.lib import build_target_lib
 from chromite.lib import commandline
 from chromite.lib import cros_build_lib
 from chromite.lib import portage_util
@@ -117,9 +117,9 @@
 
   # Translate raw options to config objects.
   name = '%s_%s' % (opts.board, opts.variant) if opts.variant else opts.board
-  opts.build_target = build_target_util.BuildTarget(name,
-                                                    build_root=opts.board_root,
-                                                    profile=opts.profile)
+  opts.build_target = build_target_lib.BuildTarget(name,
+                                                   build_root=opts.board_root,
+                                                   profile=opts.profile)
 
   opts.run_config = sysroot.SetupBoardRunConfig(
       set_default=opts.default, force=opts.force, usepkg=opts.usepkg,