CLEANUP: stream: rename "csf" and "csb" to "scf" and "scb"

These are the stream connectors, let's give them consistent names. The
patch is large (405 locations) but totally trivial.
diff --git a/src/log.c b/src/log.c
index 717a9a0..330deb8 100644
--- a/src/log.c
+++ b/src/log.c
@@ -1982,7 +1982,7 @@
 	if (likely(s)) {
 		be = s->be;
 		txn = s->txn;
-		be_conn = cs_conn(s->csb);
+		be_conn = cs_conn(s->scb);
 		status = (txn ? txn->status : 0);
 		s_flags = s->flags;
 		uniq_id = s->uniq_id;
@@ -2114,7 +2114,7 @@
 				break;
 
 			case LOG_FMT_CLIENTIP:  // %ci
-				addr = (s ? cs_src(s->csf) : sess_src(sess));
+				addr = (s ? cs_src(s->scf) : sess_src(sess));
 				if (addr)
 					ret = lf_ip(tmplog, (struct sockaddr *)addr, dst + maxsize - tmplog, tmp);
 				else
@@ -2127,7 +2127,7 @@
 				break;
 
 			case LOG_FMT_CLIENTPORT:  // %cp
-				addr = (s ? cs_src(s->csf) : sess_src(sess));
+				addr = (s ? cs_src(s->scf) : sess_src(sess));
 				if (addr) {
 					/* sess->listener is always defined when the session's owner is an inbound connections */
 					if (addr->ss_family == AF_UNIX)
@@ -2145,7 +2145,7 @@
 				break;
 
 			case LOG_FMT_FRONTENDIP: // %fi
-				addr = (s ? cs_dst(s->csf) : sess_dst(sess));
+				addr = (s ? cs_dst(s->scf) : sess_dst(sess));
 				if (addr)
 					ret = lf_ip(tmplog, (struct sockaddr *)addr, dst + maxsize - tmplog, tmp);
 				else
@@ -2158,7 +2158,7 @@
 				break;
 
 			case  LOG_FMT_FRONTENDPORT: // %fp
-				addr = (s ? cs_dst(s->csf) : sess_dst(sess));
+				addr = (s ? cs_dst(s->scf) : sess_dst(sess));
 				if (addr) {
 					/* sess->listener is always defined when the session's owner is an inbound connections */
 					if (addr->ss_family == AF_UNIX)