[Tizen] Fix compiler warning (-Wsign-compare).

[   46s] ../../../../home/abuild/rpmbuild/BUILD/crosswalk/src/xwalk/application/browser/application.cc: In member function 'GURL xwalk::application::Application::GetURLFromRelativePathKey(const string&)':
[   46s] ../../../../home/abuild/rpmbuild/BUILD/crosswalk/src/base/macros.h:74:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
[   46s]  #define arraysize(array) (sizeof(ArraySizeHelper(array)))
[   46s]                                                          ^
[   46s] ../../../../home/abuild/rpmbuild/BUILD/crosswalk/src/xwalk/application/browser/application.cc:199:27: note: in expansion of macro 'arraysize'
[Tizen] Remove unused variables.

These ones are not needed since
7514f134afdebcf056e3531dcfcfa196da11bc14, and removing them gets rid of
a few compiler warnings.
Merge pull request #2193 from rakuco/fix-tizen-warnings

[Tizen] Fix a few compiler warnings.