Fixed crash while loading page without title.

Fixed crash while loading page without title.

[Issue]     https://bugs.tizen.org/jira/browse/TT-162
[Problem]   Browser crashed while loading page.
[Cause]     There was no check if page title is empty while comparing.
[Solution]  Changed compering to URL, added check if it's empty.
[Verify]    Launch browser > go to: http://jmajnert.github.io/tests/localStorage_test/localStoragePersistance.html
            refresh page > close browser > open again > go to previous site.
            Browser shouldn't crash.

Change-Id: Icc19ad7a327d97fe6ff79777b0fc819189cf660a
Signed-off-by: Maciej Skrzypkowski <m.skrzypkows@samsung.com>