Revert "iOS: Add launch xib name to info.plist"

This reverts commit b7db78362db88852f99182b400e1a52603f2e259.
Revert "iOS: install LaunchScreen.xib"

This reverts commit 39716c68b3da13de88fe4b7c5ba068d70c84c9a8.
Revert "iOS: add LaunchScreen.xib for support iPhone 6 and 6 Plus native screen resolution"

This reverts commit 4dc6e268014d229fa7aa12cd3a5b163fbe15ff9f.