Iraqi Prime Minister Adel Abdul-Mahdi traveled to Saudi Arabia this week and met with King Salman, in a sign of deepening relations between two countries that for years had no diplomatic ties. Mr. Abdul-Mahdi, accompanied by the ministers of oil, foreign affairs and electricity, met with Saudi officials and businessmen on Thursday to discuss expanding commercial ties. On Wednesday, the two sides signed agreements in the fields of energy, power and education. But politicians and some analysts said the greater value…