BUG: extrudeMesh - partial fix for incorrect behaviour - see #1964

Changed IO flag so that new mesh is created
- was using old 'faces', 'owner' etc but then used the new patch starts

Corrected logic for contMap in polyTopoChange

applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C

@@ -704,7 +704,7 @@ int main(int argc, char *argv[])
                 regionName,
                 runTimeExtruded.constant(),
                 runTimeExtruded,
-                IOobject::READ_IF_PRESENT,  // Read fv* if present
+                IOobject::NO_READ,  // Do not read primitives, do read fv*
                 IOobject::AUTO_WRITE,
                 false
             ),