Minor language fixes:

    * Correct a grammar mistake
    * Make my own English more cromulent
    * Use GB to express Gigabytes rather than Gb, which usually
      means Gigabits.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@328728 13f79535-47bb-0310-9956-ffa450edef68