ENH: support objectRegistry::checkOut(const word& name)

- similar to what erase() does, but as a mutable operation (#1180)

- replace basicThermo lookupAndCheckout (commit 880c98757d) with
  the new objectRegistry::checkOut() method.

src/sampling/surfMeshSample/surfMeshSamplers/surfMeshSamplers.C

@@ -49,24 +49,6 @@ namespace Foam
 
 bool Foam::surfMeshSamplers::verbose_ = false;
 
-void Foam::surfMeshSamplers::checkOutNames
-(
-    const objectRegistry& registry,
-    const UList<word>& names
-)
-{
-    objectRegistry& reg = const_cast<objectRegistry&>(registry);
-
-    for (const word& fldName : names)
-    {
-        objectRegistry::iterator iter = reg.find(fldName);
-        if (iter.found())
-        {
-            registry.checkOut(*iter());
-        }
-    }
-}
-
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
@@ -297,7 +279,11 @@ bool Foam::surfMeshSamplers::execute()
         }
     }
 
-    checkOutNames(db, cleanup);
+    // Cleanup any locally introduced names
+    for (const word& fieldName : cleanup)
+    {
+        db.checkOut(fieldName);
+    }
 
     return true;
 }

src/sampling/surfMeshSample/surfMeshSamplers/surfMeshSamplers.H

@@ -157,14 +157,6 @@ class surfMeshSamplers
 
     // Private Member Functions
 
-        //- Remove items by name from objectRegistry
-        static void checkOutNames
-        (
-            const objectRegistry& registry,
-            const UList<word>& names
-        );
-
-
         //- Hard-coded derived field (rho * U)
         //  \return true if field did not previously exist
         bool add_rhoU(const word& derivedName);