Merge from Björn:

* mandos-ctl: New option "--remove-client".  Only default to listing
              clients if no clients were given on the command line.
* plugins.d/mandos-client.c: Lower kernel log level while bringing up
                             network interface.  New option "--delay"
                             to control the maximum delay to wait for
                             running interface.
* plugins.d/mandos-client.xml (SYNOPSIS, OPTIONS): New option
                                                   "--delay".