sysutils/zap: Update to version 0.6.4.

Fix issues with replication.

• Do not require all '-r dataset' arguments to be listed first.
• Fix error checking. If only one argument to 'zap rep' was supplied, replication would silently fail. This required breaking the interface. Instead of
  
  zap rep|replicate [-dLSv] [[-r dataset]... [dataset]... remote_dest]
  
  the format is now
  
  zap rep|replicate [-dLSv] [remote_dest [-r] dataset [[-r] dataset]...].

Fix issue with destroy.

• In 0.6.3 $zptn was updated in destroy() to be an extended regular expression. But, when a host was not supplied as an argument, grep -E was still being supplied with the initial $zptn value containing a basic regular expression.

With 'zap snap', do not require all '-r dataset' arguments to be listed
first.

Reviewed by: AMDmi3
Approved by: swills (mentor)
Differential Revision: https://reviews.freebsd.org/D9086