headers specified in a JS rewrite can come back as binaries.
headers specified in a JS rewrite can come back as binaries.

fixes rewrites_js JS test.

fkaempfer/couchdb,apache/couchdb-couch,fkaempfer/couchdb,cloudant/couchdb-couch,fkaempfer/couchdb,fkaempfer/couchdb,apache/couchdb-couch,cloudant/couchdb-couch,fkaempfer/couchdb,cloudant/couchdb-couch,apache/couchdb-couch,fkaempfer/couchdb