TT-165 Fixed browser crash after opening page from history/bookmarks

TT-165 Fixed browser crash after opening page from history/bookmarks

[Issue#] https://bugs.tizen.org/jira/browse/TT-165
[Problem] Browser's crash after opening a page from bookmarks/history
[Cause] Favicon was inserted into freed object
[Solution] Added disconnects from signals after closing MoreMenu
[Verify] New Tab -> MoreMenu -> History -> open page
         or New Tab -> Bookmarks -> open page
         Check if browser crashes

Please keep in mind that disconnects are needed here because views
are removed when exiting, which won't be done in future new browser's
structure.

Change-Id: I7a8db96b35d397b88196bbdbba21f526c73c2ec8