pyelftools: move to explicit import

We want to pull third_party out of implicit sys.path search,
so change importing of this module to explicit.

BUG=b:187794934
TEST=CQ passes

Change-Id: I4b2e474ee8bb1a3a8af579de05485abd36425df1
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2910246
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_fuzz.py b/scripts/cros_fuzz.py
index 5a87ad3..5d614d4 100644
--- a/scripts/cros_fuzz.py
+++ b/scripts/cros_fuzz.py
@@ -43,8 +43,6 @@
 import os
 import shutil
 
-from elftools.elf.elffile import ELFFile
-
 from chromite.lib import build_target_lib
 from chromite.lib import commandline
 from chromite.lib import constants
@@ -54,6 +52,7 @@
 from chromite.lib import osutils
 from chromite.lib import portage_util
 from chromite.third_party import lddtree
+from chromite.third_party.pyelftools.elftools.elf.elffile import ELFFile
 
 
 # Directory in sysroot's /tmp directory that this script will use for files it