util: Convert to using libtool

util: Convert to using libtool

Create a pthreaded version of libafsutil, named liboafs_util.la,
and use this library in all of the pthreaded binaries that we build,
replacing both inclusion of libafsutil.a, and direct compliation of
pthreaded versions of the util source files.

libafsutil.a is provided for legacy LWP applications, and the
convenience library libafsutil_pic.a remains until we address the way
in which the user space cache manager is built and linked.

Change-Id: Ibdc3d6e2fe56ca6f5b882cf03991d1a2e32c62b2
Reviewed-on: http://gerrit.openafs.org/8056
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>