Make arcstat.py default to one header per screen

Today arcstat.py prints one header every hdr_intr (20 by default)
lines. It would be more consistent with out utilities like vmstat
if hdr_intr defaulted to terminal window size, i.e.  one header
per screenful of outputs.

Signed-off-by: Isaac Huang <he.huang@intel.com>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2183
sighandler() should take 2 arguments

Stopping arcstat.py with ^C always ends up with error:

  TypeError: sighandler() takes no arguments (2 given)

This patch corrects the error by updating the signal handler
to take the correct number of arguments.

Signed-off-by: Isaac Huang <he.huang@intel.com>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2182
Free props in ztest_init()

Valgrind complained about this and it's absolutely right.  The
props nvlist was not being freed in ztest_init.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #2174
Switch ztest mmap(2) ASSERTs to VERIFYs

This is just a small bit of cleanup to ensure ztest fails early
on systems where mmap(2) is not functioning.  For the automated
testing which is the primary consumer of ztest there is no
functional change because debugging is always enabled.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2177
Remove unused option -r from 'zpool import'

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2178