MINOR: buffer: replace bi_fast_delete() with b_del()

There's no distinction between in and out data now. The latter covers
the needs of the former and supports wrapping. The extra cost is
negligible given the locations where it's used.
diff --git a/src/h1.c b/src/h1.c
index 5498f1f..7e19679 100644
--- a/src/h1.c
+++ b/src/h1.c
@@ -485,7 +485,7 @@
 				if (co_data(msg->chn))
 					goto http_msg_ood;
 				/* Remove empty leading lines, as recommended by RFC2616. */
-				bi_fast_delete(buf, ptr - input);
+				b_del(buf, ptr - input);
 			}
 			msg->sol = 0;
 			msg->sl.st.l = 0; /* used in debug mode */
@@ -553,7 +553,7 @@
 				if (co_data(msg->chn))
 					goto http_msg_ood;
 				/* Remove empty leading lines, as recommended by RFC2616. */
-				bi_fast_delete(buf, ptr - input);
+				b_del(buf, ptr - input);
 			}
 			msg->sol = 0;
 			msg->sl.rq.l = 0; /* used in debug mode */
diff --git a/src/hlua.c b/src/hlua.c
index 588576c..2179c61 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -5405,7 +5405,7 @@
 
 	if (htxn->s->txn) {
 		/* HTTP mode, let's stay in sync with the stream */
-		bi_fast_delete(ic->buf, htxn->s->txn->req.sov);
+		b_del(ic->buf, htxn->s->txn->req.sov);
 		htxn->s->txn->req.next -= htxn->s->txn->req.sov;
 		htxn->s->txn->req.sov = 0;
 		ic->analysers &= AN_REQ_HTTP_XFER_BODY;
diff --git a/src/proto_http.c b/src/proto_http.c
index 37360bf..85c2391 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -3385,7 +3385,7 @@
 		FLT_STRM_CB(s, flt_http_reply(s, txn->status, chunk));
 		co_inject(res->chn, chunk->str, chunk->len);
 		/* "eat" the request */
-		bi_fast_delete(req->chn->buf, req->sov);
+		b_del(req->chn->buf, req->sov);
 		req->next -= req->sov;
 		req->sov = 0;
 		s->req.analysers = AN_REQ_HTTP_XFER_BODY | (s->req.analysers & AN_REQ_FLT_END);