[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
Merge pull request #2302 from jinbang/support_python3.0+_byte_map

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