Drop mercurial formatting from .gitignore
    
    The project was managed in mercurial before converting to git in 2010.
    The .hgignore file was renamed to .gitignore in 151adde ("rename
    .hgignore to .gitignore", 2010-01-05).  Remove the 'syntax: glob' entry
    which has no meaning in git.
    
    Signed-off-by: Todd Zullinger <tmz@pobox.com>