Better BP re-setting on restart (Closes: #634227)

	* src/persp/dbgperspective/nmv-dbg-perspective.cc
	(DBGPerspective::execute_program): Save breakpoints we want to
	delete and set back. Delete them, and set them back by looking at
	the saved breakpoint. Do not pass any special cookie to
	IDebugger::delete_breakpoint anymore.
	(DBGPerspective::on_debugger_breakpoint_deleted_signal): Do not
	handle the special cookie for the restarting use case anymore.
	(<const char *I_DEBUGGER_COOKIE_EXECUTE_PROGRAM>): Remove this
	[now useless] cookie.