viced: Remove the LWP fileserver

viced: Remove the LWP fileserver

*) Remove all LWP specific code from the fileserver, and make pthread
   the default
*) Build the pthreaded fileserver in the 'viced' directory, rather than
   in tviced
*) Move the DAFS specific files from tviced to viced (arguably, these
   should move into dviced, but there are currently no source files in
   that directory)
*) Remove tviced from the build

Change-Id: I6e186c9fad6d9dccd04cf1317a80c087587ef25f
Reviewed-on: http://gerrit.openafs.org/5816
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>