btree_gin: properly call DirectFunctionCall1()

Previously we called DirectFunctionCall3() with dummy arguments.

Patch by Jon Nelson

contrib/btree_gin/btree_gin.c

@@ -318,10 +318,7 @@ GIN_SUPPORT(macaddr, false, leftmostvalue_macaddr, macaddr_cmp)
 static Datum
 leftmostvalue_inet(void)
 {
-	return DirectFunctionCall3(inet_in,
+	return DirectFunctionCall1(inet_in, CStringGetDatum("0.0.0.0/0"));
-							   CStringGetDatum("0.0.0.0/0"),
-							   ObjectIdGetDatum(0),
-							   Int32GetDatum(-1));
 }
 GIN_SUPPORT(inet, true, leftmostvalue_inet, network_cmp)
 
@@ -346,20 +343,14 @@ GIN_SUPPORT(bytea, true, leftmostvalue_text, byteacmp)
 static Datum
 leftmostvalue_bit(void)
 {
-	return DirectFunctionCall3(bit_in,
+	return DirectFunctionCall1(bit_in, CStringGetDatum(""));
-							   CStringGetDatum(""),
-							   ObjectIdGetDatum(0),
-							   Int32GetDatum(-1));
 }
 GIN_SUPPORT(bit, true, leftmostvalue_bit, bitcmp)
 
 static Datum
 leftmostvalue_varbit(void)
 {
-	return DirectFunctionCall3(varbit_in,
+	return DirectFunctionCall1(varbit_in, CStringGetDatum(""));
-							   CStringGetDatum(""),
-							   ObjectIdGetDatum(0),
-							   Int32GetDatum(-1));
 }
 GIN_SUPPORT(varbit, true, leftmostvalue_varbit, bitcmp)