remove magic number
remove magic number

nickelsberry/AXStretchableHeaderTabViewController,jkoroniak/JKStretchableHeaderTabViewController,homekuanyi/AXStretchableHeaderTabViewController,homekuanyi/AXStretchableHeaderTabViewController,homekuanyi/AXStretchableHeaderTabViewController,jkoroniak/JKStretchableHeaderTabViewController,nickelsberry/AXStretchableHeaderTabViewController,jkoroniak/JKStretchableHeaderTabViewController,akiroom/AXStretchableHeaderTabViewController,faridh/FMStretchableHeaderTabViewController,akiroom/AXStretchableHeaderTabViewController,akiroom/AXStretchableHeaderTabViewController,nickelsberry/AXStretchableHeaderTabViewController