Revert "Add extensible resources to resource tracker"

This bug added a regression to both nova-bm and ironic,
neither can deploy instances.
Fixes-bug: #1347795

This reverts commit 50b4ba4ee583d25eef10a6608172c002f9bec6f2.

Change-Id: Icc8d629467911972480b633c7808a0964c9f1c7d
Merge "Revert "Add extensible resources to resource tracker""