Fix compile errors in low level FreeBSD code.

The current lowlevel FreeBSD specific SCSI code doesn't compile
on FreeBSD. This patch at least makes sure that it compiles if it
actually works is something else.
Add FreeBSD -lcam to build flags.
Rebuild configure.
Make NDMP code compile on FreeBSD.
Fix compiler warnings.
Merge branch 'master' of https://github.com/bareos/bareos