tests: Convert opr tests to use libtool

tests: Convert opr tests to use libtool

Avoid the problems with libopr's dependencies by just converting
the tests to use the libtool version of the opr library. While we're
at it, make the tests pthreaded too.

Change-Id: I4e570b288ea57c758c848be1d545e5ee59771ab9
Reviewed-on: http://gerrit.openafs.org/8127
Reviewed-by: Jason Edgecombe <jason@rampaginggeek.com>
Tested-by: Jason Edgecombe <jason@rampaginggeek.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>