uLabel: Removed unnecessary checks for < 0

Resolves bug-report http://bugs.openfoam.org/view.php?id=2128

src/OpenFOAM/primitives/ints/uLabel/uLabel.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -47,15 +47,6 @@ Foam::uLabel Foam::pow(uLabel a, uLabel b)
         ans *= a;
     }
 
-    #ifdef FULLDEBUG
-    if (b < 0)
-    {
-        FatalErrorInFunction
-            << "negative value for b is not supported"
-            << abort(FatalError);
-    }
-    #endif
-
     return ans;
 }
 
@@ -69,10 +60,10 @@ Foam::uLabel Foam::factorial(uLabel n)
     };
 
     #ifdef FULLDEBUG
-    if (n > 12 && n < 0)
+    if (n > 12)
     {
         FatalErrorInFunction
-            << "n value out of range"
+            << "n value out of range (> 12)"
             << abort(FatalError);
     }
     #endif