analyzer: use std::unique_ptr for custom_edge_info pointers

analyzer: use std::unique_ptr for custom_edge_info pointers

gcc/analyzer/ChangeLog:
	* checker-path.cc (rewind_event::rewind_event): Update for usage of
	std::unique_ptr on custom_edge_info.
	* engine.cc (exploded_node::on_longjmp): Likewise.
	(exploded_edge::exploded_edge): Likewise.
	(exploded_edge::~exploded_edge): Delete.
	(exploded_graph::add_function_entry): Update for usage of
	std::unique_ptr on custom_edge_info.
	(exploded_graph::add_edge): Likewise.
	(add_tainted_args_callback): Likewise.
	(exploded_graph::maybe_create_dynamic_call): Likewise.
	(exploded_graph::process_node): Likewise.
	* exploded-graph.h (exploded_edge::~exploded_edge): Delete.
	(exploded_edge::m_custom_info): Use std::unique_ptr.
	(exploded_edge::add_edge): Likewise.
	* sm-signal.cc (register_signal_handler::impl_transition): Use
	make_unique.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>