libpq: Fix a few bits that didn't get the memo about COPY BOTH.

There's probably no real bug here at present, so not backpatching.
But it seems good to make these bits consistent with the rest of
libpq, so as to avoid future surprises.

Patch by me.  Review by Tom Lane.

src/interfaces/libpq/fe-protocol3.c

@@ -1566,7 +1566,8 @@ pqGetline3(PGconn *conn, char *s, int maxlen)
 	int			status;
 
 	if (conn->sock < 0 ||
-		conn->asyncStatus != PGASYNC_COPY_OUT ||
+		(conn->asyncStatus != PGASYNC_COPY_OUT &&
+		 conn->asyncStatus != PGASYNC_COPY_BOTH) ||
 		conn->copy_is_binary)
 	{
 		printfPQExpBuffer(&conn->errorMessage,
@@ -1617,7 +1618,8 @@ pqGetlineAsync3(PGconn *conn, char *buffer, int bufsize)
 	int			msgLength;
 	int			avail;
 
-	if (conn->asyncStatus != PGASYNC_COPY_OUT)
+	if (conn->asyncStatus != PGASYNC_COPY_OUT
+		&& conn->asyncStatus != PGASYNC_COPY_BOTH)
 		return -1;				/* we are not doing a copy... */
 
 	/*
@@ -1671,7 +1673,8 @@ pqEndcopy3(PGconn *conn)
 	PGresult   *result;
 
 	if (conn->asyncStatus != PGASYNC_COPY_IN &&
-		conn->asyncStatus != PGASYNC_COPY_OUT)
+		conn->asyncStatus != PGASYNC_COPY_OUT &&
+		conn->asyncStatus != PGASYNC_COPY_BOTH)
 	{
 		printfPQExpBuffer(&conn->errorMessage,
 						  libpq_gettext("no COPY in progress\n"));
@@ -1679,7 +1682,8 @@ pqEndcopy3(PGconn *conn)
 	}
 
 	/* Send the CopyDone message if needed */
-	if (conn->asyncStatus == PGASYNC_COPY_IN)
+	if (conn->asyncStatus == PGASYNC_COPY_IN ||
+		conn->asyncStatus == PGASYNC_COPY_BOTH)
 	{
 		if (pqPutMsgStart('c', false, conn) < 0 ||
 			pqPutMsgEnd(conn) < 0)