Fix to keep only lines with *

Was broken with following  `softwareupdate -l` output:

Software Update Tool
Copyright 2002-2012 Apple Inc.

Finding available software
Software Update found the following new or updated software:
   * 031-00536-5.1.0.0
        Command Line Developer Tools for OS X Mavericks (5.1.0.0), 121492K [recommended]
   * Safari7.1Mavericks-7.1
        Safari (7.1), 59574K [recommended]
   * Command Line Tools (OS X Mavericks)-6.0
        Command Line Tools (OS X 10.9) (6.0), 104398K [recommended]
   * iBooksDelta-1.0.1
        iBooks Update (1.0.1), 14334K [recommended]
   * iTunesXPatch-11.4
        iTunes (11.4), 94992K [recommended]