Set default strategy of not remembering certificate decision.

Set default strategy of not remembering certificate decision.

SSLHostStateDelegate may be left unimplemented to use a default strategy of not
remembering certificate decisions at all. As long as the default strategy is
used the GetSSLHostStateDelegate left unimplemented, thus
BrowserContextEfl::GetSSLHostStateDelegate() method should return NULL.

Bug: http://107.108.218.239/bugzilla/show_bug.cgi?id=8884
Reviewed by: Antonio Gomes, SeungSeop Park

Change-Id: I3e826a8b5116abdf2f5a9a3b8bbe590526f89008
Signed-off-by: Michal Poteralski <m.poteralski@samsung.com>