fix write quorum calculation for bucket operations (#10364)

When the number of disks is odd, the calculation of quorum 
for bucket operations were not correct, fix it.

cmd/utils.go

@@ -105,7 +105,11 @@ func getReadQuorum(drive int) int {
 }
 
 func getWriteQuorum(drive int) int {
-	return getDefaultDataBlocks(drive) + 1
+	quorum := getDefaultDataBlocks(drive)
+	if getDefaultParityBlocks(drive) == quorum {
+		quorum++
+	}
+	return quorum
 }
 
 // URI scheme constants.