[Runtime] Fix the bug that one XPK package can install multiple times
without any error report.

The XPK package should generate the application id using public key
which is contained in the header of XPK package.

BUG=https://crosswalk-project.org/jira/browse/XWALK-883
Merge pull request #1520 from takethathe/install

[Runtime] It should not be possible to install a XPK package multiple times