proto_bin: Bump 'bin_async_max_postponed_chunks' 32 -> 1024

The default of 32 chunks was too low, considering that BIN TCP conns are
very low in count (often a handful of nodes!), while also transporting
large volums of data within short periods of time (e.g. dialog/usrloc
syncs), so async data buffering may often occur.

(cherry picked from commit 1f17e30)

modules/proto_bin/doc/proto_bin_admin.xml

@@ -159,14 +159,14 @@ modparam("proto_bin", "bin_async", 0)
 		</para>
 		<para>
 		<emphasis>
-			Default value is 32.
+			Default value is 1024.
 		</emphasis>
 		</para>
 		<example>
 		<title>Set <varname>bin_async_max_postponed_chunks</varname> parameter</title>
 		<programlisting format="linespecific">
 ...
-modparam("proto_bin", "bin_async_max_postponed_chunks", 16)
+modparam("proto_bin", "bin_async_max_postponed_chunks", 1024)
 ...
 </programlisting>
 		</example>

modules/proto_bin/proto_bin.c

@@ -56,7 +56,7 @@ static int bin_send_timeout = 100;
 static struct tcp_req bin_current_req;
 static int bin_max_msg_chunks = 32;
 static int bin_async = 1;
-static int bin_async_max_postponed_chunks = 32;
+static int bin_async_max_postponed_chunks = 1024;
 static int bin_async_local_connect_timeout = 100;
 static int bin_async_local_write_timeout = 10;