[JBTM-1920] Pass enlist link header in req body (temp hack)

wildfly commit 9a3b000767c018a681a4858a84aae20a0b8c7310 (or a close earlier commit) seems to have changed the way Link headers are parsed. The PR includes a temporary hack which allows BlackTie Link headers to be passed in the enlist HTTP request body. This temporary hack is justified since the bug breaks all narayana builds and the PR allows us to investigate the problem at our leisure.