While reviewing the OpenZFS kernel interface checks I noticed that there were some improvements which could be made.  I propose making the following changes (patches to follow).

1. Enforce a minimum ZFS version of 0.7.0 (released in July 2017).  This version provides the required interfaces for all major features expected by Lustre (quotas, multihost), and dropping support for older versions let's us remove some dead code.  Setting a minimum version also allows us to fail cleanly at configure time if a required interface isn't available.
2. Update the lustre-build-zfs.m4 checks to use the parallel build functionality from LU-13485.  This reduces the ZFS configure check time to just a few seconds.
3. Update all the checks to have consistent output and be a little more strict to catch as much as possible during configure.