hal.kernel_version missing in non RTAPI versions

[andypugh]

The hal.kernel_version tag is only added if RTAI is defined.
This means that stepconf test-axis (and probably the same in pncconf) doesn't work.

problem caused at
src/hal/halmodule.cc : 1159
makes things go wrong at
src/emc/usr_intf/stepconf/stepconf.py : 724
src/emc/usr_intf/pncconf/pncconf.py : 4304

[zultron]

@luminize, addressing your question in #60, this problem applies to userland threads. Here's the code:

https://github.com/machinekit/machinekit/blob/master/src/hal/lib/halmodule.cc#L1167-L1169
https://github.com/machinekit/machinekit/blob/master/src/emc/usr_intf/stepconf/stepconf.py#L807-L808
https://github.com/machinekit/machinekit/blob/master/src/emc/usr_intf/pncconf/pncconf.py#L4222-L4223