[Android][REG] Packaging tool does not work with python 3.0+

1. command output is a bytes-like object in python3.0+,
re.findall can't use a string pattern on a bytes-like object,
encode the bytes-like object to str to fix that.
2. map function will return a map object in python3.0+,
'map' object has no attribute 'extend',
not use map function to fix that.

BUG=https://crosswalk-project.org/jira/browse/XWALK-2303
BUG=https://crosswalk-project.org/jira/browse/XWALK-2474

(cherry picked from commit 2fc758233c4790dd7860bccb2ac4ae7627a0b8f7)
Merge pull request #2458 from rakuco/backport-xwalk-2303-fix

[Android] Backport Python 3 make_apk fixes for crosswalk-8.