[Android] Make an app named with a space in it.

Android accepts the space for app name. In the previous code,
space is treated as invalid char for app name, and replaced with
'_'.

BUG=https://github.com/crosswalk-project/crosswalk/issues/767
Merge pull request #785 from junmin-zhu/space

[Android] Make an app named with a space in it.