Exit with a status of 1 when catching a wild unidentified exception

I'm pretty sure nobody ever could possibly want this to be a status of 0
(success).

src/wesnoth.cpp

@@ -870,6 +870,7 @@ int main(int argc, char** argv)
 		// some compilers will simply terminate without calling destructors if
 		// the exception isn't caught.)
 		std::cerr << "Caught unspecified general exception. Terminating." << std::endl;
+		return 1;
 #endif
 	}