Fix lint.

scripts/dev/build_release.py

@@ -29,7 +29,6 @@ import subprocess
 import argparse
 import tarfile
 import collections
-import shutil
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), os.pardir,
                 os.pardir))
@@ -178,7 +177,6 @@ def build_sdist():
         print('\n'.join(files))
 
 
-
 def main():
     """Main entry point."""
     parser = argparse.ArgumentParser()