Loading the libcfs module is getting increasingly slow due to multiple checksum types being speed tested at startup (8 checksum types * 1s each).

Reduce the number of checksum algorithms checked at module load time to the ones that are actually need the speed, and reduce the amount of time taken to compute the checksum.

The mount_facet() code also gained a 5s sleep for each target mounted when http://review.whamcloud.com/20194 was landed, which slows down tests that reformat the filesystem a lot (like conf-sanity.sh) significantly, and is in any case an annoyance for developer testing.