Minimum velocity (VBAS) for motor records

[klauer]

Default velocity of 0 will not request a motion from the PLC, but confusingly go through retries and fail:

ioc-lfe-optics> ../motorRecord.cc:1789 MR1L0:HOMS:MMS:PITCH doRetryOrDone dval=300.000000 rdbd=2.000000 spdb=0.000100 udf=0 stat=0 rcnt=0 preferred_dir=1 relpos=300.051265 relbpo
s=300.051265 drbv=-0.051265
../motorRecord.cc:1810 MR1L0:HOMS:MMS:PITCH mipSetBit 'Mo' old='' new='Mo'
../motorRecord.cc:1532 MR1L0:HOMS:MMS:PITCH motor has stopped drbv=-0.008380 pp=0 udf=0 stat=0 nsta=0 mip=0x20('Mo') msta=0x4103
../motorRecord.cc:1186 MR1L0:HOMS:MMS:PITCH maybeRetry: not close enough rdbd=2.000000 diff=300.008380 rcnt=0 mip=0x20('Mo')
../motorRecord.cc:1215 MR1L0:HOMS:MMS:PITCH mipSetVal old='Mo' new='Ry'
../motorRecord.cc:1670 MR1L0:HOMS:MMS:PITCH mipSetBit 'Dr' old='Ry' new='Ry Dr'
../motorRecord.cc:1673 MR1L0:HOMS:MMS:PITCH callbackRequestDelayed() called

Seems to indicate we should have a non-zero base velocity specified.