Link libopus as static lib into opus codec plugin


git-svn-id: http://scm.sipfoundry.org/rep/sipX/main@12219 a612230a-c5fa-0310-af8b-88eea846685b
Define path to libopus static lib


git-svn-id: http://scm.sipfoundry.org/rep/sipX/main@12220 a612230a-c5fa-0310-af8b-88eea846685b