Fix usage of the DAHDI_VMWI ioctl.

(closes issue #14090)
Reported by: alecdavis
Patches:
      chan_dahdi.VMWI_ioctl.diff.txt uploaded by alecdavis (license 585)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@164602 65c4cc65-6c06-0410-ace0-fbb531ad65f3