configure: Replace literally printed '\n' with newline

configure: Replace literally printed '\n' with newline

The idea here was to leave an empty line before the message, but by
default, echo prints '\n' literally instead of interpreting it. Use a
separate echo without parameter instead like in other places in the
script.

Fixes: 6fdc5bc173188f5e4942616b16d589500b874a15
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>