BUG/MINOR: da: Get the request channel to call CHECK_HTTP_MESSAGE_FIRST()

Since the commit 89dc49935 ("BUG/MAJOR: http_fetch: Get the channel depending on
the keyword used"), the right channel must be passed as argument when the macro
CHECK_HTTP_MESSAGE_FIRST is called.

This patch must be backported to 1.9.
diff --git a/src/da.c b/src/da.c
index 0a49d52..4559c6e 100644
--- a/src/da.c
+++ b/src/da.c
@@ -298,7 +298,7 @@
 		return 1;
 	}
 
-	CHECK_HTTP_MESSAGE_FIRST();
+	CHECK_HTTP_MESSAGE_FIRST((smp->strm ? &smp->strm->req : NULL));
 	smp->data.type = SMP_T_STR;
 
 	/**