The Hadith has more dialogue than this. And this is a Hasan Gharib Hadith. This is acted upon according to some of the people of knowledge. They say that the people of Adh-Dhimmah do not recieve a share, even it they were to fight along with the Muslims against the enemy.
Some of the people of knowledge said that they are given a share when they attend the battle with the Muslims.
In-book : Book 21, Hadith 13
English translation : Vol. 3, Book 19, Hadith 1558