Remove calls to SHAMapNode::getID

This addresses RIPD-347
Calls in SHAMap::getCache and SHAMap::canonicalize are
purposefully left in place at this time (to be removed
later).
We have already committed in many places to prefer function local statics to file-scope statics.  If these place needs beast::static_initializer treatment, so be it.  static_initializer is not an unsolvable problem.  And if it turns out we don't want to spend more time there, and this particular function local static is causing a problem on vc2013, just add a call to Masks in main().