releasetools: Make validate_target_files.py pylint clean.

C: 73, 0: Wrong hanging indentation (add 4 spaces).
      file_name, actual_sha1, expected_sha1)
      ^   | (bad-continuation)
C:171, 0: Wrong continued indentation (add 20 spaces).
        'SYSTEM/etc/recovery.img', expected_recovery_sha1)
        ^                   | (bad-continuation)
C:185, 0: Wrong continued indentation (add 20 spaces).
        file_path='IMAGES/boot.img', expected_sha1=boot_info[3])
        ^                   | (bad-continuation)
C:191, 0: Wrong continued indentation (add 20 spaces).
        file_path='IMAGES/recovery.img',
        ^                   | (bad-continuation)
C:192, 0: Wrong continued indentation (add 20 spaces).
        expected_sha1=expected_recovery_sha1)
        ^                   | (bad-continuation)
W: 67,15: Use % formatting in logging functions and pass the % parameters as arguments (logging-format-interpolation)
W:150,17: Use % formatting in logging functions and pass the % parameters as arguments (logging-format-interpolation)
W:153,15: Use % formatting in logging functions and pass the % parameters as arguments (logging-format-interpolation)
W:194,15: Use % formatting in logging functions and pass the % parameters as arguments (logging-format-interpolation)
C: 27, 0: standard import "import logging" comes before "import common" (wrong-import-order)
C: 28, 0: standard import "import os.path" comes before "import common" (wrong-import-order)
C: 29, 0: standard import "import re" comes before "import common" (wrong-import-order)
C: 31, 0: standard import "import sys" comes before "import common" (wrong-import-order)

Test: pylint --rcfile=pylintrc validate_target_files.py
Test: Run validate_target_files.py with a target-files.zip.
Change-Id: Ie64acdb4cee4326938c4ad5a34b575d7b82478c0