[Tizen IVI] Enable the platform-specific application installation logic

This patch allows "InstallPackageOnTizen" calls for Tizen IVI, so that
the platform-specific application un/installation logic is enabled there
(e.g. "pkgcmd -l" lists the installed xwalk packages). However
"InstallPackageOnTizen" can work only with Shared Process Model
application installation code path due to user permissions problems
that are not fixed within non Shared Process Model code path.

Considering all above and considering also that we should always use
Shared Process Model on Tizen, it was decided to remove non Shared
Process Model application installation code.

BUG=https://crosswalk-project.org/jira/browse/XWALK-901
Merge pull request #1698 from pozdnyakov/app_installation_on_tizen

[Tizen IVI] Enable the platform-specific application installation logic