Changelog:
- Use getops for option handling.
- Create snapshots again when a scrub is in progress.
- Let the -r flag be specified for individual datasets.
- To handle parsing the '-r' flags, the create function was broken off
into two functions: create_parse() and create(). create() creates one
snapshot per call.
- Created helper functions pool_ok and pool_scrub.
- Minor changes to warning messages.
- POSIX sh does not support local, so initialize variables intended to be
local to a function.
Approved by: swills (mentor)
Differential Revision: https://reviews.freebsd.org/D8511
380a187d40