BUG: Pair sort on construct did the opposite (fixes #1701)

src/OpenFOAM/primitives/Pair/PairI.H

@@ -2,8 +2,10 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+    \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2017-2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -68,7 +70,7 @@ inline Foam::Pair<T>::Pair(const FixedList<T, 2>& lst)
 template<class T>
 inline Foam::Pair<T>::Pair(const T& f, const T& s, const bool doSort)
 {
-    if (doSort && f < s)
+    if (doSort && s < f)
     {
         first()  = s;
         second() = f;
@@ -88,7 +90,6 @@ inline Foam::Pair<T>::Pair(const FixedList<T, 2>& lst, const bool doSort)
 {}
 
 
-
 template<class T>
 inline Foam::Pair<T>::Pair(Istream& is)
 :