[LinuxCNC/linuxcnc Issue#44] ja: motion’s joint locking hal pins missing

Skunkworks reports on IRC: http://tom-itx.no-ip.biz:81/~tom-itx/irc/logs/%23linuxcnc-devel/2016-03-09.html

Here are the steps I follow to reproduce the issue:

1. Start with a pre-ja config with at least one [AXISn]LOCKINGINDEXER=1, auto-convert to a ja config with update_ini.
2. Note that the LOCKINGINDEXER setting got applied to the correct [JOINTn] section.
3. Start linuxcnc with the converted config.
4. Linuxcnc does not create the requested joint.n.unlock and joint.n.is-unlocked HAL pins.

This is what I expected to happen:

The pins should be created.

This is what happened instead:

The pins were not created.

It worked properly before this:

Works in 2.7.4 (pre-ja), though in this version, Motion creates locking pins for all rotary axes, whether or not they asked for them in the ini.

In JA, Motion expects a new load-time argument of unlockjointsmask, which is not created by update_ini. Motion only creates locking pins for the joints enabled in that mask.

Possible fixes would be to revert to the old system of creating locking pins for all rotary joints, or to ensure that unlockjointsmask gets sent to Motion correctly at load time.