#211 rundig has problems with -a and alternative config files

[Moritz Bunkus]

rundig, if used with -a, tries to rename the newly created .work
versions to the final versions. This will fail if the user also uses an
alternative configuration file with a different database directory. The
attached patch scans rundig's command line for -c and the following
configuration file and tries to extract the database directory
parameter from it thus using the right paths.

[Moritz Bunkus]

fix for extracting the database directory