Fix streaming replication starting at the very first WAL segment.

Per complaint from Greg Stark.

src/backend/replication/libpqwalreceiver/libpqwalreceiver.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c,v 1.3 2010/02/03 09:47:19 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c,v 1.4 2010/02/25 07:31:40 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -84,8 +84,6 @@ libpqrcv_connect(char *conninfo, XLogRecPtr startpoint)
 	PGresult   *res;
 	char		cmd[64];
 
-	Assert(startpoint.xlogid != 0 || startpoint.xrecoff != 0);
-
 	/* Connect */
 	snprintf(conninfo_repl, sizeof(conninfo_repl), "%s replication=true", conninfo);
 

src/backend/replication/walsender.c

@@ -30,7 +30,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/replication/walsender.c,v 1.7 2010/02/18 11:13:46 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/replication/walsender.c,v 1.8 2010/02/25 07:31:40 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -573,15 +573,6 @@ XLogSend(StringInfo outMsg)
 	/* use volatile pointer to prevent code rearrangement */
 	volatile WalSnd *walsnd = MyWalSnd;
 
-	/*
-	 * Invalid position means that we have not yet received the initial
-	 * CopyData message from the slave that indicates where to start the
-	 * streaming.
-	 */
-	if (sentPtr.xlogid == 0 &&
-		sentPtr.xrecoff == 0)
-		return true;
-
 	/* Attempt to send all records flushed to the disk already */
 	SendRqstPtr = GetWriteRecPtr();