[Tizen] Remove unused variable.

Removed code was no longer used since removing xwalk-pkg-helper in commit 880057e.
Include cleanup in package related headers

Inclusion of redundant headers can result in a lack of inclusion of required
headers in other files.
Merge pull request #2520 from doduda/cleanup

[Tizen] Remove unused variable.
Merge pull request #2521 from tweglarski/IncludeFixAtPackageHeaders

Include cleanup in package related headers