memleak in make_external_lucid_ctx_v1()

Parfait analysis flagged a memory leak in lucid_context.c:

Memory allocated here:
179    /* Allocate the structure */
180    if ((lctx = xmalloc(bufsize)) == NULL) {
181        retval = ENOMEM;
182        goto error_out;
183    }

but never freed when function returns here:
217    else {
218        return EINVAL;  /* XXX better error code? */
219    }