BUG: potential fix for stale fvMesh addressing - see #1956

Failures shown in interFoam cases were found to be a result of stale ldu
addressing in fvMesh.  Potentially delete lduPtr_ alone, but likely safer to
clear all addressing:

    // deleteDemandDrivenData(lduPtr_);
    clearAddressing(true);

src/finiteVolume/fvMesh/fvMesh.C

@@ -278,6 +278,10 @@ bool Foam::fvMesh::init(const bool doInit)
 
         // Intialise my data
         polyMesh::init(doInit);
+
+        // All addressing needs to be updated
+        // deleteDemandDrivenData(lduPtr_);
+        clearAddressing(true);
     }
 
     // Check the existence of the cell volumes and read if present