Fix fontification of C++ declaration with type FOO::FOO.

Fix fontification of C++ declaration with type FOO::FOO.

* lisp/progmodes/cc-engine.el (c-find-decl-spots): Initialize
cfd-top-level properly.
(c-forward-decl-or-cast-1): On finding FOO::FOO, check it is followed by "("
before deciding it is a constructor.

* lisp/progmodes/cc-fonts.el (c-font-lock-complex-decl-prepare): Negate the
result of the c-bs-at-toplevel-p call passed to c-font-lock-declarators
(simple bug fix).