takes: TkSlf4j can fail for specific request

Hi. If TkSlf4j wraps Take that returns empty response (without body), and if POST request with some body has been sent through VerboseWire (from jcabi-http), RqMethod.Base will fail with this exception:

java.io.IOException: Invalid HTTP method: X-Takes-LocalAddress:
    at org.takes.rq.RqMethod$Base.method(RqMethod.java:127)
    at org.takes.tk.TkSlf4j.act(TkSlf4j.java:105)
    at org.takes.http.BkBasic.print(BkBasic.java:108)
    at org.takes.http.BkBasic.accept(BkBasic.java:84)
    at org.takes.http.BkParallel$1$1.run(BkParallel.java:89)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

Test for reproducing:

    @Test
    public void test() throws IOException {
        new FtRemote(
            new TkSlf4j(
                req -> new RsEmpty()
            )
        ).exec(
            home ->
                new JdkRequest(home)
                    .method("POST")
                    .body().set("test").back()
                    .through(VerboseWire.class)
                    .fetch()
                    .as(RestResponse.class)
                    .assertStatus(HttpURLConnection.HTTP_OK)
        );
    }

Environment: java - 1.8.0_102-b14 takes - 1.1 jcabi-http - 1.16

http:

POST / HTTP/1.1
Cache-Control: no-cache
Pragma: no-cache
User-Agent: Java/1.8.0_102
Host: localhost:41997
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
Content-type: application/x-www-form-urlencoded
Content-Length: 4

testHTTP/1.1 200 OK

HTTP/1.1 500 Internal Error
Content-Length: 538
Content-Type: text/plain

java.io.IOException: Invalid HTTP method: X-Takes-LocalAddress:
.at org.takes.rq.RqMethod$Base.method(RqMethod.java:127)
.at org.takes.tk.TkSlf4j.act(TkSlf4j.java:105)
.at org.takes.http.BkBasic.print(BkBasic.java:108)
.at org.takes.http.BkBasic.accept(BkBasic.java:84)
.at org.takes.http.BkParallel$1$1.run(BkParallel.java:89)
.at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
.at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
.at java.lang.Thread.run(Thread.java:745)