Remove hashes.json check (#828)

Plaso supports the --no-hashes switch so old check removed.

turbinia/workers/artifact.py

@@ -52,6 +52,7 @@ def run(self, evidence, result):
     cmd = [
         'sudo',
         'image_export.py',
+        '--no-hashes',
         '--logfile',
         image_export_log,
         '-w',
@@ -78,12 +79,6 @@ def run(self, evidence, result):
 
     for dirpath, _, filenames in os.walk(export_directory):
       for filename in filenames:
-        if filename == 'hashes.json' and dirpath == export_directory:
-          # Ignore the hashes.json file created by image export.
-          # TODO: remove this when
-          # https://github.com/log2timeline/plaso/pull/3320
-          # is pushed.
-          continue
         exported_artifact = ExportedFileArtifact(
             artifact_name=self.artifact_name, source_path=os.path.join(
                 dirpath, filename))