Add node/node_type attribute "no_clflush".
This is for FreeBSD to turn off use of the CLFLUSH instruction via the hw.clflush_disable loader var. We have encountered some opteron machines on which this causes problems. The attribute can be set for the node_type (via the web page for editing node types) or the node (via brute-force SQL hackary) to override whatever FreeBSD would do by default. This attribute is passed via tmcd to the diskloader MFS which will fixup the loader.conf file post-frisbee.