be more explicit in From...Require becuase PG does not support this completely yet :-/

bea044cc · Ralf Jung · 2ba9728f · bea044cc
Commit bea044cc authored Feb 27, 2016 by Ralf Jung
--- a/algebra/frac.v
+++ b/algebra/frac.v
-From Coq Require Import Qcanon.
+From Coq.QArith Require Import Qcanon.
 From algebra Require Export cmra.
 From algebra Require Import functor upred.
 Local Arguments validN _ _ _ !_ /.