Fix typo in morphisms

Thanks to Matthew Emerton
http://stacks.math.columbia.edu/tag/0CN7#comment-2225

morphisms.tex

@@ -10598,7 +10598,7 @@ \section{Universal homeomorphisms of affine schemes}
 \medskip\noindent
 Continuing, we see that $B$ is integral over $B'$ 
 (Algebra, Lemma \ref{algebra-lemma-integral-permanence})
-which implies $\Spec(B') \to \Spec(B)$ is surjective
+which implies $\Spec(B) \to \Spec(B')$ is surjective
 (Algebra, Lemma \ref{algebra-lemma-integral-overring-surjective}).
 Thus if $A \to B$ induces purely inseparable extensions of residue fields,
 then the same is true for $A \to B'$. This proves the case