Fix PPD copy bug, and add check for MIME database.

Fix PPD copy bug, and add check for MIME database.

scheduler/conf.c:
    - ReadConfiguration(): Add check for NULL MIME database (due
      to misconfiguration or missing ServerRoot...)

scheduler/ipp.c:
    - copy_model(): Use select() with timeout and pipe to catch
      when the cups-driverd process is done.

git-svn-id: svn+ssh://src.apple.com/svn/cups/cups.org/trunk@4700 7a7537e8-13f0-0310-91df-b6672ffda945